Les oeufs

% des protéines	Nom commun	Nom IUIS	Fonction	Masse
54	Ovalbumine	Gal d 2	Serpine	44 et+
12	Ovotransferrine (= conalbumine)	Gal d 3	Transferrine	78
11	Ovomucoïde	Gal d 1	Inhibiteur de type Kazal	28
8 ?	G2 et G3 globulines
3,5	Ovomucine			8000
3,4	Lysozyme	Gal d 4	Hydrolase	14
1,5	Ovoinhibiteur		Inhibiteur de type Kazal	63-69
1	Ovoglycoprotéine		Lipocaline	37-42
0,5	Ovostatine			780
0,05	Cystatine			11
0,05	Avidine			60

	Nb sujets	Age (ans)	Prévalence (%)	Seuil (kU/l)	VPP (%)
Caffarelli 1995	33	Méd. 2	42	0,35	60
Sampson 1997	126	Moy. 5,2	73	2 6	90 96
Boyano-M. 2001	81	Moy. 1,3	79	0,35	94
Roehr 2001	42	Méd. 1,1	67	17,5	100
Monti 2002	107	Moy. 1,3	67	17,5 50	91 95
Rancé 2003	185	Méd. 2,1	54	7,5	100
Ricci 2003	57	Moy. 3,2	56	10	100
Ando 2008	70	Méd. 2,8	41	7,4 10	89 95

	Nb sujets	Age (ans)	Prévalence (%)	Seuil (kU/l)	VPP (%)
Norgaard 1992	13	(adultes)	54	0,35 17,5	58 60
Norgaard 1995	15	(adultes)	60	0,35 17,5	69 75
Ispano 1996		(adultes)		0,35	100

	Nb sujets	Age (ans)	Prévalence (%)	Seuil (kU/l)	Probabilité d’allergie (%)
Sampson 2001	100	Méd. 3,8	80	7	95
Osterballe 2001	56	Méd. 2,2	63	1,5	100
Celik-B. 2005	41	< 1	67	4,2 10,9 88,6	90 95 99
186	≥ 1	6,7 13,2 58,2	90 95 99
Mehl 2006	424	Méd. 1,1	66	15,9 75,5	95 99
Komata 2007 <8841>	764	< 1	49	13	95
≥ 2	30	95
Ostblom 2008	111	4		13	90
Benhamou 2008	35	Méd. 3,9	69	8,2 17,5	90 95
Ott 2008	60	< 2	75	6,1 8,5 13,9	90 95 99
≥ 2	9,9 12,3 17,6	90 95 99

	Nb sujets	Age (ans)	Prévalence (%)	Seuil (kU/l)	VPP (%)
Norgaard 1995	15	(adultes)	60	0,35 17,5	73 70
Boyano-M. 2001	81	Moy. 1,3	79	0,35	98
Monti 2002	107	Moy. 1,3	67	3,5 17,5	90 100
Rancé 2003	100	Méd. 2,1	54	5,5	97

	Nb sujets	Age (ans)	Prévalence (%)	Seuil (kU/l)	VPP ou Probab. (%)
Lemon-M. 2008	117	Moy. 6,9	30	75 100	50 (Probab.) 65
Ando 2008	108	Méd. 2,8	35	4,4 62	68 (VPP) 95

Egg allergy is one of the most common food allergies in infants and young children. The great majority is not life-threatening and management involves exclusion of egg from the diet and regular review with the expectation that the majority of children will outgrow the allergy by school age. Judgment is required as to when the dietary elimination of egg is no longer required. This decision may be helped by demonstrating loss of sensitivity by skin prick or specific IgE testing and in some cases a supervised food challenge. Particular issues in management arise with more severe, potentially life-threatening reactions, with immunization with vaccines prepared in eggs, with the diagnosis of egg hypersensitivity as a cause of delayed exacerbations of eczema which can be non-IgE mediated, and in deciding whether a child can be allowed to ingest small amounts of cooked egg through egg-containing foods while continuing to avoid raw egg or larger amounts of whole egg. Cases which illustrate these issues are presented.

↩

[3] - Illi S, von Mutius E, Lau S, Nickel R, Niggemann B, Sommerfeld C, et al. The pattern of atopic sensitization is associated with the development of asthma in childhood. J Allergy Clin Immunol 2001;108:709-714

BACKGROUND: Even though atopic sensitization has been shown to be strongly associated with childhood asthma, asthma eventually develops in only one third of atopic children . OBJECTIVE: The aim of this study was to prospectively investigate the pattern of atopic sensitization typically associated with the development of asthma in childhood . METHODS: The German Multicenter Allergy Study followed 1314 children from birth to the age of 7 years. Parental questionnaires on asthma and asthmatic symptoms were completed 6 times up to the age of 2 years and from then on yearly. Determination of specific IgE to 9 food and inhalant allergens was performed yearly, and at the age of 7 years, a bronchial histamine challenge was conducted . RESULTS: Onset of atopic sensitization in atopic children with current asthma at the age of 7 years was significantly earlier than in atopic children without current asthma (39.4% before age 1 year vs 21.0%, P =.015). Early atopic sensitization without any sensitization to inhalant allergens at the age of 7 years conferred no increased risk for asthma at this age. Only those children sensitized to any allergen early in life and sensitized to inhalant allergens by the age of 7 years were at a significantly increased risk of being asthmatic at this age (odds ratio, 10.12; 95% CI, 3.81-26.88). However, even in this group of persistently sensitized children, the risk of being asthmatic at the age of 7 years was only increased if a positive parental history of asthma or atopy was present (odds ratio, 15.56; 95% CI, 5.78-41.83), with the effect being strongest for maternal asthma . CONCLUSION: Our results indicate that an underlying factor pertaining to asthma and maternal transmission may determine both a certain pattern of sensitization and the expression of asthma.

↩

[4] - Hattevig G, Kjellman B, Bjorksten B. Appearance of IgE antibodies to ingested and inhaled allergens during the first 12 years of life in atopic and non-atopic children. Pediatr Allergy Immunol 1993;4:182-186

The appearance and course of serum immunoglobulin E-antibodies (IgE-ab) to egg-white (EW), cow's milk (CM) and inhalants (pollen, danders and mite) were followed from birth to 12 years of age in 84 children unselected for family history of atopy. During the follow-up 36 children developed atopic symptoms and 48 children did not. IgE-ab to EW and CM reached a peak prevalence at 8 months of age--with high concentrations almost exclusively in atopics and disappeared successively during childhood. IgE-ab to inhalants appeared from 2 years of age and then in increasing frequency during childhood. Similar to the pattern of IgE-ab to EW and CM, transient low levels of IgE-ab to inhalants were commonly encountered in non-atopic children while high concentrations without tendency to decline were almost exclusively seen in atopics. High responders to EW-antigen during infancy were usually also high responders to inhalants during childhood. Clinical allergy to EW and CM and subsequent tolerance appeared early in childhood, whereas allergy to inhalants appeared later and did not disappear. The temporary low-grade IgE antibody response in non-atopic individuals to eaten and inhaled allergens is similar to the results of animal studies demonstrating a transient IgE production followed by tolerance.

↩

[5] - Leser C, Hartmann AL, Praml G, Wüthrich B. The "egg-egg" syndrome: occupational respiratory allergy to airborne egg proteins with consecutive ingestive egg allergy in the bakery and confectionery industry. J Investig Allergol Clin Immunol 2001;11:89-93

Allergies to various inhalative allergens are a serious problem in the bakery and confectionery industry. Sensitization to wheat flour and enzymes such as -amylase are a frequent cause of occupational asthma. Airborne egg allergens have been reported as another cause of respiratory allergy. We examined bakery and confectionery workers with respiratory symptoms due to egg aerosols. Skin tests (SPT), scratch tests (ST), nasal provocation tests (NPT) and serological examinations (IgE) were performed. Lung function was assessed by spirometry, and continuous registration of aerosols and particulates as well as gravimetric sampling was done at the workplace. Four bakery and two confectionery workers intensively exposed to airborne egg proteins suffered from conjunctivitis and rhinitis, four also from asthma. Subsequently, three of these four workers reported symptoms after ingestion of food that contained egg. SPT with commercial egg white and egg yolk extracts were negative in four cases. Only two employees had clearly positive SPT to commercial egg allergens and reacted also to wheat flour extracts. Scratch tests with native egg proteins were positive in four employees. Specific IgE to egg white and egg yolk were positive (CAP fd 2) in three and in four cases, respectively, whereas they were negative in two cases. Elevated levels of specific IgE to lysozyme were detected in four employees. Two workers were sensitized to lysozyme but not to other egg proteins. The clinical relevance of egg sensitization was confirmed by continuous air sampling and by correlating the onset of the respiratory symptoms which were reflected by a significant decline (fd30%) of the forced one second capacity (FEV1) in two workers. Sieving of egg white powder and an inadequate spray station for liquid eggs were identified as sources of excessive allergen exposure. Bakery and confectionery workers exposed to airborne egg proteins are at risk of developing occupational asthma and subsequent nutritive egg allergy. To our knowledge, these are the first cases of inhalative egg allergy and subsequent nutritive egg allergy reported in the literature, which we refer to as the "egg-egg syndrome" in analogy to the already known "bird-egg" and "egg-bird" syndromes.

↩

[6] - Hoffman DR, Guenther DM. Occupational allergy to avian proteins presenting as allergy to ingestion of egg yolk. J Allergy Clin Immunol 1988;81:484-488

↩

[7] - Bernstein JA, Kraut A, Bernstein DI, Warrington R, Bolin T, Warren CP, et al. Occupational asthma induced by inhaled egg lysozyme. Chest 1993;103:532-535

A 26-year-old man employed in a company which manufactured hen egg white derived lysozyme for use in the pharmaceutical industry was evaluated for occupational asthma. The worker began to experience immediate-onset asthmatic symptoms two months after starting to work with egg lysozyme powder. The work process involved the production of approximately 1,000 kg of purified dried lysozyme powder per week. Prick skin testing was positive to egg lysozyme (50 mg/ml) and other egg protein components, but negative to whole egg white and egg yolk reagents. Serum specific IgE to egg lysozyme was documented. Decrements in serial peak expiratory flow rates were associated with lysozyme exposure at work. A specific bronchoprovocation challenge to lysozyme powder was positive demonstrating an isolated immediate asthmatic response (48 percent decrease from baseline FEV1). This is the first reported case of lysozyme-induced asthma specifically caused by inhalational exposure to egg lysozyme

↩

[8] - Alessandri C, Calvani M Jr, Rosengart L, Madella C. Anaphylaxis to quail egg. Allergy 2005;60:128-129

↩

[9] - Langeland T. A clinical and immunological study of allergy to hen's egg white. Allergy 1983;38:399-412

The occurrence of proteins cross-reacting with allergens in hen's egg white was studied in turkey, duck, goose and seagull egg whites, in hen egg yolk, and in hen and chicken sera and flesh. The study was based upon quantitative immunoelectrophoretic techniques. The different egg whites were all found to contain proteins cross-reacting with most of the allergens in hen's egg white, but the degree of cross-reactivity varied considerably among the various egg whites. All egg whites contained proteins able to bind human IgE-antibody in the sera of patients with allergy to hen's egg white. Several proteins cross-reacting with allergens in hen's egg white were also detected in egg yolk and in hen and chicken sera and flesh. Clinical implications of the results are discussed.

↩

[10] - Verdura TE, Múgica MV, Tejedor MA, Lindo DP, Moro M, Rosado A, et al. Allergy to quail egg. Allergy 2007;62(suppl. 83):331

Background: Hen eggs are a frequent cause of food allergy. However, hypersensitivity to other avian eggs proteins are very unusual and unknown. We report a rare cause of food allergy due to quail egg in a woman without allergy to hen eggs. A 32 year old woman suffered an episode of cough, dyspnea, generalized itching and swelling of face and eyelids immediately after eating fried quail eggs dish. This episode lasted 24 h despite being treated with hydrocortisone and dexclorfeniramine. After this episode she continued eating hen eggs with tolerance but not quail egg. Previously she had tolerated quail eggs for a longtime. Methods: Skin prick test with commercially available extracts of hen egg proteins and specific serum IgE were measured. Prick-prick test with raw and cooked quail egg were also made. SDS-PAGE electrophoresis and IgE immunoblotting with white and yolk extract from quail egg were carried out and compared with similar assays applied to hen and duck egg extracts. Results: The skin test and specific IgE were negative to hen egg proteins. Prick-prick test were positive to raw white and yolk from quail egg, and negative to cooked white and yolk from quail egg. IgE immunoblotting showed an isolated band around 37 Kda in white quail egg extract but not in extracts of hen and duck egg. Conclusions: This is un unusual case of type I hypersensitivity to quail eggs without hen egg allergy. According to molecular weight the responsible allergen seems to be ovomucoid from quail egg. The phylogenetic distance between quail and other avian species may be the cause for which no cross- reactivity was found.

↩

[11] - Caro Contreras FJ, Giner Muñoz MT, Martin Mateos MA, Plaza Martin AM, Sierra Martinez JI, Lombardero M. Allergy to quail's egg without allergy to chicken's egg. Case report. Allergol Immunopathol (Madr) 2008;36:234-237

INTRODUCTION: We present a case of quail's egg allergy without allergy to chicken's egg. CASE: Girl of 10.5 years old who presents anaphylactic reaction after she ate an uncooked quail's egg. She had eaten boiled quail's egg before. She eats chicken's eggs without clinical symptoms. METHODS: We made a prick to chicken's egg and prick-by-prick to uncooked quail's and raw chicken's egg. We determined specific IgE to chicken's egg; electrophoresis and IgE by inmunoblot to eggs from chicken, duck, goose, and quail. RESULTS: We obtained negative results to prick, prick-by-prick and specific IgE to chicken's egg. Prick-by-prick to quail's egg was positive. By immunoblot we recognised a protein in quail's egg white, which is ovotransferrin without any similar bands in other species' eggs. CONCLUSIONS: The protein that we recognised is a specific protein of quail's egg. These proteins did not cross-react with proteins of chicken's egg. Cooking may degrade such proteins.

↩

[12] - Guerin-Dubiard C, Pasco M, Molle D, Desert C, Croguennec T, Nau F. Proteomic analysis of hen egg white. J Agric Food Chem 2006;54:3901-3910

Hen egg white is an original biological fluid in which major proteins have been widely studied, unlike the minor components. In this study, two-dimensional electrophoresis associated with mass spectrometry enabled the separation of 69 protein spots and their matching with major proteins, which were already known, and with minor proteins. Sixteen proteins were identified, and among them, two had never been previously detected in hen egg white, i.e., Tenp, a protein with strong homology with a bacterial permeability-increasing protein family (BPI), and VMO-1, an outer layer vitelline membrane protein. Thirteen proteins present a very wide polymorphism (ovotransferrin, ovomucoid, clusterin, etc.), some of them up to nine isoforms (ovoinhibitor). Eleven functional protein families were identified (serpin, transferrin, protease inhibitors Kazal, glycosyl hydrolases, lipocalin, bactericidal permeability-increasing protein, clusterin, UPAR/CD59/Ly6/ snake neurotoxin, cysteine protease inhibitor, VMO-1, and folate receptor families). These various biological functions could be interesting for further valorizations. In addition, three spots remain unidentified, probably because these proteins are not yet indexed in the international protein databanks.

↩

[13] - Jacobsen B, Hoffmann-Sommergruber K, Have TT, Foss N, Briza P, Oberhuber C, et al. The panel of egg allergens, Gal d 1-Gal d 5: Their improved purification and characterization. Mol Nutr Food Res 2008;52(suppl. 2):S176-S185

Egg proteins represent one of the most important sources evoking food allergic reactions. In order to improve allergy diagnosis, purified and well-characterized proteins are needed. Although the egg white allergens Gal d 1, 2, 3 and 4 (ovomucoid, ovalbumin, ovotransferrin, and lysozyme) are commercially available, these preparations contain impurities, which affect exact in vitro diagnosis. The aim of the present study was to set up further purification protocols and to extend the characterization of the physicochemical and immunological properties of the final batches. The egg white allergens Gal d 1-4 were purified from commercial preparations, whereas Gal d 5 (alpha-livetin) was purified from egg yolk. The final batches of Gal d 1-5 consisted of a range of isoforms with defined tertiary structure. In addition, the IgE binding capacity of the purified egg allergens was tested using allergic patients' sera. The allergen batches will be further used to set up allergen specific diagnostic assays and to screen a larger collection of patients' sera.

↩

[14] - Mine Y, Yang M. Recent Advances in the Understanding of Egg Allergens: Basic, Industrial, and Clinical Perspectives. J Agric Food Chem 2008;56:4874-4900

The emergence of egg allergy has had both industrial and clinical implications. In industrialized countries, egg allergy accounts for one of the most prevalent food hypersensitivities, especially in children. Atopic dermatitis represents the most common clinical manifestation in infancy; however, the range of clinical signs is broad and encompasses life-threatening anaphylaxis. The dominant egg allergens are proteins and are mainly present in the egg white, for example, ovalbumin, ovomucoid, ovotransferrin, and lysozyme. However, egg yolk also displays low-level allergenicity, for example, alpha-livetin. Strict avoidance of the offending food remains the most common recommendation for egg-allergic individuals. Nevertheless, the omnipresence of egg-derived components in prepackaged or prepared foods makes it difficult. Therefore, more efficient preventive approaches are investigated to protect consumers from inadvertent exposure and ensuing adverse reactions. On the one hand, commercial kits have become readily available that allow for the detection of egg contaminants at trace levels. On the other hand, attempts to produce hypoallergenic egg-containing products through food-processing techniques have met with promising results, but the approach is limited due to its potentially undesirable effects on the unique functional and sensory attributes of egg proteins. Therefore, the development of preventive or curative strategies for egg allergy remains strongly warranted. Pilot studies have suggested that oral immunotherapy (IT) with raw or cooked preparations of egg may represent a safe alternative, immediately available to allergic subjects, but remains applicable to only nonanaphylactic patients. Due to the limitations of conventional IT, novel forms of immunotherapy are sought based on information obtained from the molecular characterization of major egg allergens. In the past decade, promising approaches to the treatment and prevention of egg allergy have been explored and include, among others, the production of hypoallergenic recombinant egg proteins, the development of customized peptides, and bacterial-mediated immunotherapy. Nonspecific approaches have also been evaluated, and preliminary trials with the use of probiotic bacteria have yielded encouraging results. The current understanding of egg allergens offers novel approaches toward the making of food products safe for human consumption and the development of efficient immunotherapeutic strategies.

↩

[15] - Cooke SK, Sampson HA. Allergenic properties of ovomucoid in man. J Immunol 1997;159:2026-2032

Ovomucoid, the dominant allergen in hen's egg, is a highly glycosylated protein comprising 186 amino acids arranged in three tandem domains (Gal d 1.1, 1.2, and 1.3). The purpose of this study was to evaluate the allergenic properties of ovomucoid. The three ovomucoid domains were isolated and evaluated with sera from egg allergic patients to determine B cell domain specificity, B cell epitopes, and the relative importance of linear and conformational structures and carbohydrate chains to B cell epitopes. Peripheral blood T cells from egg allergic patients were used to evaluate T-dominant domains and reactivity to reduced and oxidized ovomucoid. There was significantly more IgE activity to the second ovomucoid domain (median percentage of ovomucoid-specific IgE: Gal d 1.2, 40%; Gal d 1.1, 23%; Gal d 1.3, 26%). Quantities of patient IgG Ab were comparable for all three domains. Five IgE and seven IgG binding regions were identified. IgE Ab binding to reduced ovomucoid and IgG binding to oxidized ovomucoid were significantly reduced compared with that to native ovomucoid (28 and 69%, respectively). Peripheral blood T cells of 21 of 33 patients reacted to Gal d 1.3, 18 of 33 reacted to Gal d 1.2, and 18 of 33 reacted to Gal d 1.1. T cell proliferation in vitro in response to reduced and oxidized ovomucoid were significantly greater than that in response to the native protein. These results indicate a dichotomy between T and B cell domain dominance, and the presence of both unique and common IgE and IgG epitopes. Furthermore, the results suggest that conformational B cell epitopes play a more significant role in ovomucoid allergenicity than previously appreciated, and that carbohydrate moieties have a minor effect on allergenicity.

↩

[16] - Huntington JA, Stein PE. Structure and properties of ovalbumin. J Chromatogr B Biomed Appl 2001;756:189-198

"Ovalbumin is a protein of unknown function found in large quantities in avian egg-white. Surprisingly, ovalbumin belongs to the serpin family although it lacks any protease inhibitory activity. We review here what is known about the amino acid sequence, post-translational modifications and tertiary structure of ovalbumin. The properties of ovalbumin are discussed in relation to their possible functional significance. These include reasons for failure of ovalbumin to undergo a typical serpin conformational change involving the reactive centre loop, which explains why ovalbumin is not a protease inhibitor, and also the natural conversion of ovalbumin to the more stable ""S"" form."

↩

[17] - Silverman GA, Bird PI, Carrell RW, Church FC, Coughlin PB, Gettins PGW, et al. The Serpins Are an Expanding Superfamily of Structurally Similar but Functionally Diverse Proteins. J Biol Chem 2001;276:33293-33296

↩

[18] - Moneret-Vautrin DA, Astier CMN, Franck P, Morisset M, Codreanu F, Roitel O, et al. Assessment of the Potential Cross-Allergenicity between Hen's Egg Lysozyme and Recombinant Human Lysozyme. J Allergy Clin Immunol 2007;119(1 suppl):S109

RATIONALE: Human lysozyme (rhu lys) extracted from genetically modified rice is available and regulatory strategies are currently under evaluation. Since the sequence of human lysozyme shows 60% homology with hen's egg lysozyme, and because egg lysozyme is recognized by 35% of sera from egg allergic patients, searching for a possible cross-allergenicity between human and egg lysozyme is needed. This is in keeping with the recommendations from the WHO/FAO Joint Expert Committee and the Codex Alimentarius Commission. METHODS: Forty-one sera from egg allergic patients, with specific IgE to egg lysozyme were screened by ELISA inhibition using egg lysozyme and rhu lys. Basophil activation tests (BAT) were performed in 28 egg lysozyme-sensitized patients using 3 preparations of rhu lys with a purity of 85%, 95% and 99%, human milk lysozyme, and rice proteins. Sera from 5 patients not allergic to egg were used as controls. RESULTS: In the tested sera, ELISA inhibition showed no cross-reactivity between human and hen egg lysozyme. Positive BAT to rhu lys in patients was associated to positive BAT to rice extract. The percentage of basophil activation decreased with the increase of the purity of rhu lys, consistent with the notion that contaminating rice proteins are responsible for the BAT positive responses. No positive BAT test was observed with human milk lysozyme. CONCLUSIONS: Our data support the conclusion that rhu lys does not cross react with human IgE directed against hen egg lysozyme.

↩

[19] - Frémont S, Kanny G, Nicolas JP, Moneret-Vautrin DA. Prevalence of lysozyme sensitization in an egg-allergic population. Allergy 1997;52:224-228

An egg protein, lysozyme, is a still unlabeled additive currently used in cheese preparation. Furthermore, the WHO-FAO committee considers it innocuous. However, 31% of children and 8% of adults with food allergies are allergic to eggs. This work aimed to determine the percentage of patients sensitized to lysozyme from a population of egg-allergic patients. Specific IgE was determined with Cap RAST in 52 patients clinically allergic to egg. Thirty-five percent of egg-allergic patients had antilysozyme IgE. Given this high incidence of lysozyme sensitization, it seems that the presence of lysozyme should be indicated on food labels.

↩

[20] - Pérez-Calderón R, Gonzalo-Garijo MA, Lamilla-Yerga A, Mangas-Santos R, Moreno-Gastón I. Recurrent Angioedema Due to Lysozyme Allergy. J Investig Allergol Clin Immunol 2007;17:264-266

A 54-year-old woman suffered an episode of dyspnea and edema affecting her eyelids, tongue, and lips a few minutes after intake of Lizipaina (bacitracin, papain, and lysozyme). She was treated with intravenous drugs and her symptoms improved within 2 hours. She had experienced 3 to 4 bouts of similar symptoms related to the ingestion of cured cheeses or raw egg. Specific serum immunoglobulin (Ig) E against lysozyme was present at a concentration of 0.45 kU/L, and no specific IgE was found against egg white and yolk, ovalbumin, or ovomucoid. Skin prick tests were positive with commercial extracts of egg white and lysozyme but doubtful with yolk, ovalbumin, and ovomucoid. Prick-to-prick tests with raw egg white and yolk gave positive results, but negative results were obtained with cooked egg white and yolk and 5 brands of cheese (3 of them containing lysozyme and the other 2 without lysozyme). Controlled oral administration of papain, bacitracin, and cheeses without lysozyme was well tolerated. We suggest that the presence of lysozyme in a pharmaceutical preparation, cured cheese, and raw egg was responsible for the symptoms suffered by our patient, probably through an IgE-mediated mechanism.

↩

[21] - Artesani MC, Donnanno S, Cavagni G, Calzone L, D'Urbano L. Egg sensitization caused by immediate hypersensitivity reaction to drug-containing lysozyme. Ann Allergy Asthma Immunol 2008;101:105

↩

[22] - Hytonen VP, Maatta JA, Niskanen EA, Huuskonen J, Helttunen KJ, Halling KK, et al. Structure and characterization of a novel chicken biotin-binding protein A (BBP-A). BMC Struct Biol 2007;7:8

"BACKGROUND: The chicken genome contains a BBP-A gene showing similar characteristics to avidin family genes. In a previous study we reported that the BBP-A gene may encode a biotin-binding protein due to the high sequence similarity with chicken avidin, especially at regions encoding residues known to be located at the ligand-binding site of avidin . RESULTS: Here, we expand the repertoire of known macromolecular biotin binders by reporting a novel biotin-binding protein A (BBP-A) from chicken. The BBP-A recombinant protein was expressed using two different expression systems and purified with affinity chromatography, biochemically characterized and two X-ray structures were solved - in complex with D-biotin (BTN) and in complex with D-biotin D-sulfoxide (BSO). The BBP-A protein binds free biotin with high, ""streptavidin-like"" affinity (Kd ~ 10-13 M), which is about 50 times lower than that of chicken avidin. Surprisingly, the affinity of BBP-A for BSO is even higher than the affinity for BTN. Furthermore, the solved structures of the BBP-A--BTN and BBP-A--BSO complexes, which share the fold with the members of the avidin and lipocalin protein families, are extremely similar to each other . CONCLUSION: BBP-A is an avidin-like protein having a beta-barrel fold and high affinity towards BTN. However, BBP-A differs from the other known members of the avidin protein family in thermal stability and immunological properties. BBP-A also has a unique ligand-binding property, the ability to bind BTN and BSO at comparable affinities. BBP-A may have use as a novel material in, e.g. modern bio(nano)technological applications."

↩

[23] - Enríquez-Matas A, Ibañez Sandin MD, Martínez J, Postigo I, Escudero C, Fuentes Aparicio V. Egg allergy caused by avidin. Allergy 2007;62(suppl. 83):331-332

Background: Egg proteins allergy is the most common food allergy in chilhood. Mayor allergens (ovalbumin, ovomucoid, ovotransferrin and lysozyme) are contained in egg white. Case report: A 2- year-old boy experienced an acute episode of vomiting, cough and urticaria appearing within a few minutes after eating adapted cow's milk formula for the first time. After allergologic studies he was diagnosed of cow's milk allergy and sensitizacion to hen's egg proteins, so he was prescribed a milk and egg-free diet. When he was 13 months old, he suffered an acute episode of severe local urticaria after incidental contact with raw egg. In following visits, the allergy work-up showed persistence of egg and milk proteins sensitizacion in skin prick tests but specific IgE to egg and egg proteins were negative. The study was completed when the patient was 2 years old. RESULTS: Skin prick test (mm): egg: 4; egg white: 7; egg yolk: 5: ovalbumin: 5; ovomucoid: negative. Specific IgE (CAP) to egg, white egg, yolk egg, ovalbumin, ovomucoid (two different determinations in different laboratories) were negative (< 0.35 kU/L). Controlled open oral challenge test with egg: He presented immediately conjunctival injection, perioral erythema and hives, cough and vomiting after eating 1cc of raw egg white. Egg white, egg yolk and ovalbumin extracts SDS-IgE inmunoblotting: The patient serum revealed only one IgE-binding band of approximately 60 kDa in egg white extract that could be avidin in its quaternary structure (tetrameric). CONCLUSIONS: Avidin is a hen's egg protein identified as possible allergen. However, we are not aware of any description of food allergy to avidin. We report the first case of IgE-mediated egg allergy due to avidin sensitization.

↩

[24] - Guerin-Dubiard C, Pasco M, Molle D, Desert C, Croguennec T, Nau F. Proteomic analysis of hen egg white. J Agric Food Chem 2006;54:3901-3910

Hen egg white is an original biological fluid in which major proteins have been widely studied, unlike the minor components. In this study, two-dimensional electrophoresis associated with mass spectrometry enabled the separation of 69 protein spots and their matching with major proteins, which were already known, and with minor proteins. Sixteen proteins were identified, and among them, two had never been previously detected in hen egg white, i.e., Tenp, a protein with strong homology with a bacterial permeability-increasing protein family (BPI), and VMO-1, an outer layer vitelline membrane protein. Thirteen proteins present a very wide polymorphism (ovotransferrin, ovomucoid, clusterin, etc.), some of them up to nine isoforms (ovoinhibitor). Eleven functional protein families were identified (serpin, transferrin, protease inhibitors Kazal, glycosyl hydrolases, lipocalin, bactericidal permeability-increasing protein, clusterin, UPAR/CD59/Ly6/ snake neurotoxin, cysteine protease inhibitor, VMO-1, and folate receptor families). These various biological functions could be interesting for further valorizations. In addition, three spots remain unidentified, probably because these proteins are not yet indexed in the international protein databanks.

↩

[25] - Frémont S, Kanny G, Nicolas JP, Moneret-Vautrin DA. Prevalence of lysozyme sensitization in an egg-allergic population. Allergy 1997;52:224-228

An egg protein, lysozyme, is a still unlabeled additive currently used in cheese preparation. Furthermore, the WHO-FAO committee considers it innocuous. However, 31% of children and 8% of adults with food allergies are allergic to eggs. This work aimed to determine the percentage of patients sensitized to lysozyme from a population of egg-allergic patients. Specific IgE was determined with Cap RAST in 52 patients clinically allergic to egg. Thirty-five percent of egg-allergic patients had antilysozyme IgE. Given this high incidence of lysozyme sensitization, it seems that the presence of lysozyme should be indicated on food labels.

↩

[26] - Holen E, Elsayed S. Characterization of four major allergens of hen egg-white by IEF/SDS- PAGE combined with electrophoretic transfer and IgE- immunoautoradiography. Int Arch Allergy Appl Immunol 1990;91:136-141

The antigenic and allergenic epitope maps of the hen egg-white ovalbumin, ovomucoid, ovotransferrin and lysozyme were obtained using one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis and two-dimensional sodium dodecyl sulfate gel electrophoresis following isoelectric focusing. The isoelectric points of egg-white proteins were assigned by the isoelectric focusing technique. Two-dimensional electrophoresis following isoelectric focusing provided further information regarding epitope mapping. Furthermore, electrophoretic transfer of the proteins to nitrocellulose and subsequent immunoautoradiography, clearly demonstrated the allergenicity of these proteins. An important benefit of these methods was confirming that lysozyme bound strongly to IgE in all the human sera from egg-allergic individuals and that lysozyme, in addition to ovalbumin, ovomucoid and ovotransferrin, was one of the major allergens of hen egg-white

↩

[27] - Ofori-Anti AO, Ariyarathna H, Chen L, Lee HL, Pramod SN, Goodman RE. Establishing objective detection limits for the pepsin digestion assay used in the assessment of genetically modified foods. Regul Toxicol Pharmacol 2008;52:94-103

RATIONALE: Guidelines for assessing the potential allergenicity of genetically modified (GM) organisms recommend testing the digestibility of the introduced protein by pepsin. Previous studies detailed the digestion procedure but have not described a simple objective measurement of the extent of digestion nor evaluated the impact of variation in pepsin activity. METHODS: Samples of eight proteins were digested by pepsin at pH 1.2 and 2.0 using standard conditions (10,000 U of pepsin activity per mg test protein) as well as 5000 and 20,000 units per mg of test protein. An independent digestion assay of hemoglobin was used to verify pepsin activity for each assay. Digestion was stopped in timed samples between 0.5 and 60 min. Digestion samples and undigested protein (10% and 100%) were separated by SDS-PAGE. Residual stained protein bands were measured by image analysis. RESULTS: The differences in pH and pepsin concentration only had minor effects on digestion of intermediately stable proteins: concanavalin A, ovalbumin, and lysozyme, but not on rapidly digested or stable proteins. CONCLUSIONS: Verification of pepsin activity and measurement of an objective endpoint of digestion (e.g. (90%) should provide more comparable results for the safety assessment of novel food proteins.

↩

[28] - Ott H, Baron JM, Heise R, Ocklenburg C, Stanzel S, Merk HF, et al. Clinical usefulness of microarray-based IgE detection in children with suspected food allergy. Allergy 2008;63:1521-1528

BACKGROUND: Component-resolved diagnostics using microarray technology has recently been introduced into clinical allergology, but its applicability in children with food allergy has hardly been investigated so far. The aim of this study was to evaluate the utility of microarray-based IgE detection in the diagnostic workup of food allergy and to compare this new diagnostic tool with established methods of allergen-specific IgE detection . METHODS: We investigated 130 infants and children with suspected allergy to cow's milk (CM) or hen's egg (HE). Serum IgE measurements, skin prick tests, allergen microarray assays and controlled oral food challenges with HE and CM were performed . RESULTS: We analyzed 145 oral challenges that served as reference parameters for assay performance assessment. On this basis, the panel of microarrayed allergen components was shown to represent a comprehensive repertoire of clinically relevant CM and HE proteins. Additionally, the implemented CM and HE components respectively sufficed for equivalent test performance as compared to the corresponding fluorescence enzyme immunoassay extract and skin testing. However, component-resolved diagnostics for HE and CM allergy did not make oral food challenges superfluous. Clinical IgE decision points predicting positive oral food challenges could be calculated for both in vitro test methods . CONCLUSIONS: Allergen microarrays provide a new tool to diagnose symptomatic CM and HE allergy. They show performance characteristics comparable to the current diagnostic tests and may be indicated in small children in whom only small blood volumes are obtainable. However, they are not capable of replacing double-blind, placebo-controlled food challenges in most cases.

↩

[29] - Thomas K, Aalbers M, Bannon GA, Bartels M, Dearman RJ, Esdaile DJ, et al. A multi-laboratory evaluation of a common in vitro pepsin digestion assay protocol used in assessing the safety of novel proteins. Regul Toxicol Pharmacol 2004;39:87-98

Rationale. Evaluation of the potential allergenicity of proteins derived from genetically modified foods has involved a weight of evidence approach that incorporates an evaluation of protein digestibility in pepsin. Currently, there is no standardized protocol to assess the digestibility of proteins using simulated gastric fluid. Potential variations in assay parameters include: pH, pepsin purity, pepsin to target protein ratio, target protein purity, and method of detection. The objective was to assess the digestibility of a common set of proteins in nine independent laboratories to determine the reproducibility of the assay when performed using a common protocol. Methods. A single lot of each test protein and pepsin was obtained and distributed to each laboratory. The test proteins consisted of Ara h 2 (a peanut conglutin-like protein), beta-lactoglobulin, bovine serum albumin, concanavalin A, horseradish peroxidase, ovalbumin, ovomucoid, phosphinothricin acetyltransferase, ribulose diphosphate carboxylase, and soybean trypsin inhibitor. A ratio of 10U of pepsin activity/microg test protein was selected for all tests (3:1 pepsin to protein, w:w). Digestions were performed at pH 1.2 and 2.0, with sampling at 0.5, 2, 5, 10, 20, 30, and 60min. Protein digestibility was assessed from stained gels following SDS-PAGE of digestion samples and controls. Results. Results were relatively consistent across laboratories for the full-length proteins. The identification of proteolytic fragments was less consistent, being affected by different fixation and staining methods. Overall, assay pH did not influence the time to disappearance of the full-length protein or protein fragments, however, results across laboratories were more consistent at pH 1.2 (91% agreement) than pH 2.0 (77%). Conclusions. These data demonstrate that this common protocol for evaluating the in vitro digestibility of proteins is reproducible and yields consistent results when performed using the same proteins at different laboratories.

↩

[30] - Eigenmann PA. Allergie à l'œuf. Rev Fr Allergol Immunol Clin 2003;43:450-454

L'allergie à l'oeuf est généralement diagnostiquée chez le jeune enfant. Elle est provoquée le plus souvent par une réaction IgE-médiée. Le diagnostic est rendu difficile chez certains enfants par la présence d'une sensibilisation, en l'absence d'une allergie clinique, en relation avec le terrain atopique. Un test de provocation alimentaire standardisé permettra alors de clarifier le diagnostic. L'immunisation avec des vaccins produits sur des cellules embryonnaire aviaires pose un problème particulier chez le patient allergique à l'oeuf. L'innocuité de la vaccination rougeole-oreillon-rubéole a été établie. Lorsque une indication a été posée pour une vaccination contre la grippe, la fièvre jaune, l'encéphalite à tique, ou la rage, des tests devront être conduit par l'allergologue avant la vaccination.

↩

[31] - Jolivet P, Boulard C, Beaumal V, Chardot T, Anton M. Protein components of low-density lipoproteins purified from hen egg yolk. J Agric Food Chem 2006;54:4424-4429

To identify apoproteins present in purified low-density lipoproteins from hen egg yolk in relation with their emulsifying properties, they have been separated by SDS-PAGE. We identified two different proteins by liquid chromatography-tandem mass spectrometry analysis of the peptides obtained by the trypsin digestion of protein gel bands. Apovitellenin I was identified as a monomer and a dimer. Its amino acid sequence was totally confirmed, and molecular mass determination by liquid chromatography-mass spectrometry showed that it did not present post-translational modifications but only a slight heterogeneity by the loss of one or two amino acids at the C-terminal part of the protein. Apolipoprotein B was identified into seven bands corresponding to fragments resulting of a processing of the hen blood apo-B protein. The identity of the fragments was determined by the observation of the sequence coverage by trypsin peptides and the sequence alignment with homologous human blood apolipoprotein B-100.

↩

[32] - Nguyen M, Des Roches A, Paradis L, Primeau M, Singer S. Tolerance to cooked egg in an egg allergic population. EAACI 22th Congress, Paris, 7-11 June, 2003, Poster n°611

Background: Egg alllergy is the most common food allergy in pediatric practice. Persistance of the allergy over the age of five years occur even though egg is tolerated when cooked. There is a paucity of literature describing this phenomenon. Objectives: The purpose of this study was to determine the percentage of children, who while being allergic to egg, are able to tolerate it in its cooked form. The usefulness of skin prick tests to predict the outcome of cooked egg food challenge was studied. Methods: Between January 1998 and May 2002, 60 children allergic to egg performed an oral food challenge to cooked egg (cake). Results: Table: Cooked egg (cake) food challenge Positive Negative p N (%) 16 (27%) 44 (73%) Age (year) 6.9 5.9 0.23 Number of other food allergies 3.9 2.5 0.04 SPT (mm) total egg 9.7 6.8 0.03 white 10.1 6.4 0.001 yolk 9.5 6.0 0.07 SPT: skin prick test t-test analysis Conclusion: 73% of egg allergic children could tolerate cooked egg. Perhaps cooking denatures sufficient proteins as to render the egg toleratable. The results of the skin prick tests and number of other food allergies are helpful in predicting children who will tolerate cooked egg.

↩

[33] - Besler M, Steinhart H, Paschke A. Stability of food allergens and allergenicity of processed foods. J Chromatogr B Biomed Appl 2001;756:207-228

The allergenicity of food could be altered by several processing procedures. For various foods of animal and plant origin the available literature on this alteration is described. Investigations on hidden allergens in food products are also dealt with. [References: 160

↩

[34] - Romeira AM, Pires G, Gaspar A, Arêde C, Morais-Almeida M, Rosado-Pinto J. Egg allergy – to be or not to be boiled. Allergy 2003;58:533-534

↩

[35] - Eigenmann PA. Allergie à l'œuf. Rev Fr Allergol Immunol Clin 2003;43:450-454

L'allergie à l'oeuf est généralement diagnostiquée chez le jeune enfant. Elle est provoquée le plus souvent par une réaction IgE-médiée. Le diagnostic est rendu difficile chez certains enfants par la présence d'une sensibilisation, en l'absence d'une allergie clinique, en relation avec le terrain atopique. Un test de provocation alimentaire standardisé permettra alors de clarifier le diagnostic. L'immunisation avec des vaccins produits sur des cellules embryonnaire aviaires pose un problème particulier chez le patient allergique à l'oeuf. L'innocuité de la vaccination rougeole-oreillon-rubéole a été établie. Lorsque une indication a été posée pour une vaccination contre la grippe, la fièvre jaune, l'encéphalite à tique, ou la rage, des tests devront être conduit par l'allergologue avant la vaccination.

↩

[36] - Hefle SL. Impact of processing on food allergens. Adv Exp Med Biol 1999;459:107-119

In general, allergenic foods are resistant to processes commonly used in food manufacturing. Nearly all the causative proteins (allergens) retain their allergenicity after treatment by heat and/or proteolysis. Notable exceptions exist; for example, the allergenicity of many fresh fruits and vegetables is decreased or removed by relatively mild processes such as gentle heating or mashing. The use of proteolytic enzymes to remove allergenicity is successfully used in the production of hypoallergenic infant formulas, but this approach with other allergenic foods has resulted in only limited success. Processing effects can result in decreased or complete removal of allergenic qualities of a food, such as the removal of proteins in oilseed processing, which renders the oils hypoallergenic and safe for consumption by allergic individuals. This discussion will address the different allergenic foods and processes which can affect or decrease their allergenicity. [References: 101]

↩

[37] - Sanchez C, Frémont S. Conséquences des traitements thermiques et de la formulation sur la structure et l'allergénicité des protéines alimentaires. Rev Fr Allergol Immunol Clin 2003;43:13-20

Une augmentation importante du nombre de cas d'allergies alimentaires a été constatée au cours des cinq dernières années. Parmi les causes possibles, les procédés alimentaires et les interactions entre ingrédients et additifs sont fortement suspectés. Cette revue présente l'état des connaissances sur la relation entre chauffage, formulation, structure et allergénicité des protéines. Les procédés de fabrication alimentaire comprennent un ensemble d'opérations unitaires thermiques et mécaniques dont l'objet est de structurer, texturer et permettre une conservation satisfaisante de l'aliment. Les opérations de chauffage entraînent dans la plupart des cas une dénaturation irréversible de la conformation de la protéine pouvant conduire à son agrégation. Ces changements structuraux ne sont pas corrélés avec une diminution du potentiel allergénique des protéines. Selon les cas, un chauffage peut n'avoir aucun effet, diminuer ou augmenter ce potentiel. L'existence d'épitopes séquentiels et conformationnels, le démasquage de nouveaux épitopes ou la modification d'épitopes par réaction de Maillard peut expliquer partiellement les résultats reportés dans la littérature. Des interactions entre protéines allergènes et autres molécules présentes dans les aliments peuvent entraîner des modifications conformationnelles des protéines, même sans chauffage, et affecter leur stabilité thermique. En particulier, une augmentation ou une diminution de l'agrégation thermique des protéines peuvent être observées. L'effet de ces interactions sur le potentiel allergénique des protéines est aujourd'hui pratiquement inconnu.

↩

[38] - Joo K, Kato Y. Assessment of allergenic activity of a heat-coagulated ovalbumin after in vivo digestion. Biosci Biotechnol Biochem 2006;70:591-597

We often eat heat-coagulated (H-C) food proteins, but there have been few studies on the allergenic activity of H-C proteins after digestion and absorption in vivo. To show that H-C protein is not an allergen after digestion, mice were used to investigate the digestion and absorption of the protein through the intestinal epithelium into portal blood employing immunoblotting and competitive inhibition ELISA. Ovalbumin (OVA) was used as the model protein, and H-C OVA was prepared by heating a 5% OVA solution for 15 min in boiling water. Antigenic OVA was not detected in the soluble fraction of gastrointestinal contents or the portal blood of mice administered H-C OVA. Also, voluntary physical activities, as an assessment of anaphylaxis, were monitored for 15 h using OVA sensitized mice. Compared to the voluntary physical activities of sensitized mice without any load, no decrease in activity was observed in the group administered H-C OVA, but a significant decrease in activity was found in the mice administered unheated OVA. These results strongly indicate that H-C OVA does not retain allergenic properties.

↩

[39] - Matsuda T, Matsubara T, Hino S. Immunogenic and allergenic potentials of natural and recombinant innocuous proteins. J Biosci Bioeng 2006;101:203-211

A new aspect of protein immunogenic and allergenic properties has become important recently, when there is a higher chance that our immune system will be exposed to novel protein antigens and/or familiar protein antigens with an unprecedented high frequency and large amount. These proteins are innocuous, nontoxic, and noninvasive by themselves, and include various natural proteins from the environment and recombinant proteins from industry. The technical term allergenic has been used for such proteins and their abilities to induce specific IgE production and to cross-link IgE/Fc epsilonRI on the surface of mast cells and basophiles have been recognized. As for the environmental proteins, some physicochemical properties (solubility, stability, and permeability across a mucosal epithelium) of the proteins indirectly play important roles in their allergenic potential because they do not originate from invasive pathogens as vehicles. Indeed, several lines of experimental evidences have been accumulated indicating that all proteins are absorbed across mucosal epithelia by transcellular transport and/or through interstitial spaces among the epithelial cells but not at equal levels. Some animal models have been established for natural sensitization to some allergenic proteins by feeding or intragastric administration without an adjuvant and, in a few cases, some symptoms resembling human allergy and even anaphylaxis have been induced by oral challenge with the proteins. Sometimes, even to self-proteins, the immunogenic or allergenic potential is given by post-translational modifications and possibly by unknown structural/conformational alterations, when they are exogenous self-proteins, such as recombinant human proteins for drug use. Despite the accumulation of knowledge and the progress in analytical technology on protein allergenicity, it is still crucial to predict the allergenic potential of novel and unused proteins. However, some animal models are applicable for assessing the relative allergenic potential of processed proteins in comparison with that of native proteins in preclinical studies.

↩

[40] - Host A, Samuelsson EG. Allergic reactions to raw, pasteurized, and homogenized/pasteurized cow milk: a comparison. A double- blind placebo- controlled study in milk allergic children. Allergy 1988;43:113-118

Five children aged 12-40 months with IgE-mediated adverse reactions to cow milk (immediate onset clinical pattern of cow milk allergy) were orally challenged double-blind in random order with three different milk preparations processed from the same batch of milk 1) raw untreated cow milk, 2) pasteurized cow milk, 3) homogenized and pasteurized cow milk, and 4) Nutramigen (a commercial hypoallergenic infant formula based on hydrolysed casein) as placebo. Skin prick tests with the same preparations were also performed. On oral challenge the three different processed milk types provoked significant and similar allergic reactions in each child, and no adverse reactions followed the challenge with placebo (Nutramigen). Skin prick test with the same milk products were positive in all children and comparable to the results with an extract of purified raw cow milk protein (Soluprick), whereas Nutramigen did not elicit any skin reactions. A tendency towards a lower threshold of reaction and larger skin reactions induced by the processed milk preparations might indicate an increased ability of pasteurized and homogenized/pasteurized milk to evoke allergic reactions in patients allergic to milk.

↩

[41] - Mine Y, Zhang JW. Comparative studies on antigenicity and allergenicity of native and denatured egg white proteins. J Agric Food Chem 2002;50:2679-2683

The binding activities of IgG and IgE antibodies from egg-allergic patients to physically or chemically treated egg white proteins were examined and compared with those of rabbit anti-egg white IgG antibodies. The sera from eight patients and four rabbit antibodies were used in this study. The binding activities of human IgG antibody to partially denatured ovotransferrin (Tf), ovalbumin (OA), and lysozyme (Lys) forms were increased, whereas carboxymethylation (RCM) and heat treatment caused a dramatic decrease in the antigenicity of Tf and ovomucoid (OVM). Tf and OVM were major immunogenic antigens for the rabbit IgG response. Urea also caused Tf to exhibit greater rabbit IgG binding activity. In contrast, human and rabbit antibodies did not react with ovomucin. Partially denatured Tf and Lys also induced strong IgE binding activities. The allergenicity of Tf, OVM, and Lys was decreased by RCM, whereas OA retained its binding capacity. These results suggested that anti-OA IgE recognizes more sequential epitopes and that anti-OVM and Lys antibodies recognize both conformational and sequential epitopes. Tf and OVM were dominant allergens for the IgE antibodies of anaphylaxis patients, whereas IgE from atopic patients bound more strongly with OA and OVM.

↩

[42] - Hefle SL. Impact of processing on food allergens. Adv Exp Med Biol 1999;459:107-119

In general, allergenic foods are resistant to processes commonly used in food manufacturing. Nearly all the causative proteins (allergens) retain their allergenicity after treatment by heat and/or proteolysis. Notable exceptions exist; for example, the allergenicity of many fresh fruits and vegetables is decreased or removed by relatively mild processes such as gentle heating or mashing. The use of proteolytic enzymes to remove allergenicity is successfully used in the production of hypoallergenic infant formulas, but this approach with other allergenic foods has resulted in only limited success. Processing effects can result in decreased or complete removal of allergenic qualities of a food, such as the removal of proteins in oilseed processing, which renders the oils hypoallergenic and safe for consumption by allergic individuals. This discussion will address the different allergenic foods and processes which can affect or decrease their allergenicity. [References: 101]

↩

[43] - Ando H, Movérare R, Kondo Y, Tsuge I, Tanaka A, Borres MP, et al. Utility of ovomucoid-specific IgE concentrations in predicting symptomatic egg allergy. J Allergy Clin Immunol 2008;122:583-588

Grass pollens are one of the most important airborne allergen sources worldwide. About 20 species from five subfamilies are considered to be the most frequent causes of grass pollen allergy, and the allergenic relationships among them closely follow their phylogenetic relationships. The allergic immune response to pollen of several grass species has been studied extensively over more than three decades. Eleven groups of allergens have been identified and described, in most cases from more than one species. The allergens range from 6 to 60 kD in apparent molecular weight and display a variety of physicochemical properties and structures. The most complete set of allergens has so far been isolated and cloned from Phleum pratense (timothy grass) pollen. Based on the prevalence of IgE antibody recognition among grass pollen-sensitized individuals, several allergens qualify as major, but members of two groups, groups 1 and 5, have been shown to dominate the immune response to grass pollen extract. Isoform variation has been detected in members of several of the allergen groups, which in some cases can be linked to observed genetic differences. N-linked glycosylation occurs in members of at least three groups. Carbohydrate- reactive IgE antibodies have been attributed to grass pollen sensitization and found to cross-react with glycan structures from other allergen sources, particularly vegetable foods. Another cause of extensive cross-reactivity are the group 12 allergens (profilins), which belong to a family of proteins highly conserved throughout the plant kingdom and present in all tissues. Members of eight allergen groups have been cloned and expressed as recombinant proteins capable of specific IgE binding. This development now allows diagnostic dissection of the immune response to grass pollen with potential benefits for specific immunotherapy.

↩

[44] - Takagi K, Teshima R, Okunuki H, Itoh S, Kawasaki N, Kawanishi T, et al. Kinetic Analysis of Pepsin Digestion of Chicken Egg White Ovomucoid and Allergenic Potential of Pepsin Fragments. Int Arch Allergy Immunol 2005;136:23-32

BACKGROUND: The allergenic potential of chicken egg white ovomucoid (OVM) is thought to depend on its stability to heat treatment and digestion. Pepsin-digested fragments have been speculated to continue to exert an allergenic potential. OVM was digested in simulated gastric fluid (SGF) to examine the reactivity of the resulting fragments to IgE in sera from allergic patients . METHODS: OVM was digested in SGF and subjected to SDS-PAGE. The detected fragments were then subjected to N-terminal sequencing and liquid chromatography/mass spectrometry/mass spectrometry analysis to confirm the cleavage sites and partial amino acid sequences. The reactivity of the fragments to IgE antibodies in serum samples from patients allergic to egg white was then determined using Western blotting (n=24) . RESULTS: The rate of OVM digestion depended on the pepsin/OVM ratio in the SGF. OVM was first cleaved near the end of the first domain, and the resulting fragments were then further digested into smaller fragments. In the Western blot analysis, 93% of the OVM-reactive sera also bound to the 23.5- to 28.5-kDa fragments, and 21% reacted with the smaller 7- and 4.5-kDa fragments . CONCLUSION: When the digestion of OVM in SGF was kinetically analyzed, 21% of the examined patients retained their IgE-binding capacity to the small 4.5-kDa fragment. Patients with a positive reaction to this small peptide fragment were thought to be unlikely to outgrow their egg white allergy. The combination of SGF-digestibility studies and human IgE-binding experiments seems to be useful for the elucidation and diagnosis of the allergenic potential of OVM.

↩

[45] - Kato Y, Oozawa E, Matsuda T. Decrease in antigenic and allergenic potentials of ovomucoid by heating in the presence of wheat flour: dependence on wheat variety and intermolecular disulfide bridges. J Agric Food Chem 2001;49:3661-3665

The antigenic and allergenic activities of ovomucoid (OM) remaining in soluble fractions of pasta-like model samples of wheat flour mixed with egg white were investigated by ELISA competitive inhibition and immunoblotting analyses using a rabbit anti-OM IgG and the serum IgE specific for OM in patients allergic to egg white. The mixture of egg white and wheat flour of soft, hard, and durum varieties was kneaded for 10-50 min and benched for 1 h at RT, and then small pieces of the dough were heated in boiling 1% NaCl solution for 15 min. Even before heating, only after the kneading for 30 min or more, but not after kneading for only 20 min, followed by the benching, the antigenic activity of OM which remained in the phosphate-buffered saline extract from the dough markedly decreased. Almost no antigenic activity of OM was detected in the extracts of heated samples. Furthermore, in the extracts of heated durum samples, only a trace of or almost no IgE-reactive OM was detected against the five patients' sera. These reductive effects of wheat on the OM antigenicity and allergenicity were more remarkable in the durum variety than in the others. No detectable proteins were extracted with 1% SDS from the heated samples, whereas OM was extracted with 1% SDS containing 10% 2-mercaptoethanol, suggesting heat-induced polymerization through intermolecular disulfide bonds among OM and wheat.

↩

[46] - Faeste CK, Lovberg KE, Lindvik H, Egaas E. Extractability, stability, and allergenicity of egg white proteins in differently heat-processed foods. J AOAC Int 2007;90:427-436

Hen's egg white protein is a major cause of food allergy, and a considerable number of countries have introduced labeling directions for processed food products. To control compliance with these regulations, analytical assays for the detection of egg in manufactured foods have been developed. In this study, we have tested the performance of 3 commercially available kits for quantitative egg analysis using 6 model heat-processed foods. The 3 assays worked well under standard conditions with soluble egg white proteins, but only the kit using a denaturing-reducing extraction buffer detected egg in complex heat-treated food matrixes. The differently extracted food samples were further used to evaluate the stability and allergenicity of the egg white allergens ovalbumin, ovomucoid, ovotransferrin, and lysozyme with polyclonal anti-egg antibodies and sera of 6 patients with egg allergy. It could be shown that differences in egg protein extractability have a significant impact on the interpretation of study results

↩

[47] - Huang FR, Lemon-Mulé H, Bencharitiwong R, Sampson HA, Nowak-Wegrzyn AH. Effect of Heating and Food Matrix on Egg White (EW) Protein Allergenicity. J Allergy Clin Immunol 2009;123:S180

RATIONALE:We recently reported that 70% of egg-allergic children tolerate extensively-heated egg. We sought to explore the effects of heating and food matrix on EW protein allergenicity. METHODS: EW, purified ovalbumin, and ovomucoid powders were incrementally heated in a boiling water bath at 90 8C for up to 90 minutes; raw EW, scrambled EW, hard boiled EW, egg-containing muffin, waffle, egg noodle and meatball were compared by SDS-PAGE electrophoresis and by immunolabeling, utilizing pooled sera from children reactive to heated-egg (mean EW-IgE 18 kUA/L), tolerant to heated-egg (mean EW-IgE 5.3 kUA/L), and those who tolerated unheated-egg (mean EWIgE 5.3 kUA/L). RESULTS: Electrophoresis of incrementally heatedEWidentified several protein fractions including ovalbumin and ovomucoid. The ovalbumin band became progressively weaker, whereas ovomucoid remained stable after 25 minutes of heating. Immunoblot studies utilizing pooled sera from egg-allergic children showed the strongest binding to rawEW, scrambled EW, hard-boiled EW, and meatball, followed by waffle, egg noodle, and muffin. Furthermore, there was greater IgE binding of EW proteins in all forms by pooled sera from children who reacted to heated-egg, compared to those who tolerated heated-egg or unheated-egg. There was no difference in IgE binding between children who tolerated heated-egg and those who tolerated unheated-egg. CONCLUSIONS: Immunologically identifiable ovalbumin decreased with heating, whereas ovomucoid remained stable. Extensive heating and unavailability of EW proteins within the food matrix reduces allergenicity of EW. Children reactive to heated-egg show greater binding to EW proteins than children who are tolerant to heated-egg.

↩

[48] - Quirce S, Marañón F, Umpierrez A, De las Heras M, Fernández-Caldas E, Sastre J. Chicken serum albumin (Gal d 5) is a partially heat-labile inhalant and food allergen implicated in the bird-egg syndrome. Allergy 2001;56:754-762

BACKGROUND: Chicken serum albumin (alpha-livetin) has been implicated as the causative allergen of the bird-egg syndrome. However, the clinical relevance of sensitization to this allergen has not been confirmed by specific challenge tests and environmental sampling. We investigated whether chicken albumin can be detected in air samples collected in a home with birds, and whether sensitization to this protein may cause respiratory and food allergy symptoms. The heat resistance of chicken albumin and the possible cross-reactivity with conalbumin were also investigated . METHODS: We studied eight patients with food allergy to egg yolk who also suffered from respiratory symptoms (rhinitis and/or asthma) caused by exposure to birds. Sensitization to egg yolk and bird antigens was investigated by skin and serologic tests. Hypersensitivity to chicken albumin was confirmed by specific bronchial, conjunctival, and oral provocation tests . RESULTS: All patients had positive skin tests and serum IgE against egg yolk, chicken serum, chicken meat, bird feathers, and chicken albumin. The presence of airborne chicken albumin in the domestic environment was confirmed. Specific bronchial challenge to chicken albumin elicited early asthmatic responses in six patients with asthma. An oral challenge with chicken albumin provoked digestive and systemic allergic symptoms in the two patients challenged. IgE reactivity to chicken albumin was reduced by 88% after heating at 90 degrees C for 30 min. ELISA inhibition demonstrated only partial cross-reactivity between chicken albumin and conalbumin . CONCLUSION: Chicken albumin (Gal d 5) is a partially heat-labile allergen that may cause both respiratory and food-allergy symptoms in patients with the bird-egg syndrome.

↩

[49] - Urisu A, Ando H, Morita Y, Wada E, Yasaki T, Yamada K, et al. Allergenic activity of heated and ovomucoid-depleted egg white. J Allergy Clin Immunol 1997;100:171-176

BACKGROUND: No egg white products have been clearly proven to be hypoallergenic. The role of egg white proteins in allergic reactions to eggs is still debatable . OBJECTIVE: This study was designed to determine the importance of ovomucoid, an egg white protein, in the development of allergies to egg white . METHODS: We performed a double-blind, placebo-controlled food challenge in subjects with high levels of IgE antibodies for egg white to compare the allergenicities of heated and ovomucoid-depleted egg white, freeze-dried egg white, and heated egg white. Levels of IgE antibodies for egg white, ovomucoid, ovalbumin, ovotransferrin, and lysozyme were measured in serum by RAST . RESULTS: Twenty-one of 38 subjects with positive challenge responses to freeze-dried egg white had negative challenge responses to heated egg white, whereas 16 of 17 subjects (94.1%) with positive responses to heated egg white did not respond to the heated and ovomucoid-depleted egg white challenge. The subjects with positive challenge responses to freeze-dried egg white tended to have higher IgE antibody values to ovomucoid than those with negative responses. IgE antibody levels to ovomucoid were significantly higher in subjects with positive responses to a challenge with heated egg white than in those with no response. There were no significant differences in the levels of IgE antibodies to the other proteins, except ovomucoid, in the negative-response and positive-response groups in challenge tests with freeze-dried and heated egg white . CONCLUSION: The heated and ovomucoid-depleted egg white preparation was less allergenic than heated or freeze-dried preparations. Ovomucoid has a more important role in the pathogenesis of allergic reactions to egg white than other proteins in egg white.

↩

[50] - Astwood JD, Leach JN, Fuchs RL. Stability of food allergens to digestion in vitro. Nat Biotechnol 1996;14:1269-1273

One of the concerns regarding the development of genetically modified foods is the introduction of allergenic molecules, predominantly proteins. Prospective testing for allergenic proteins from sources with no prior history of causing allergy is hampered by the absence of suitable techniques and models. Stability to digestion was tested as a candidate physicochemical property for use in distinguishing allergenic proteins from non-allergenic proteins. A simple model of gastric digestion was tested using some major food allergens (peanut Ara h2 and lectin, soybean [beta]-conglycinin subunits, SKTI and Gly m BD 30K, mustard Bra J IE, milk casein and [beta]-lactoglobulin, bovine serum albumin, and several egg proteins). Soybean [beta]-conglycinin was stable for 60 min; in comparison, a non-allergenic protein (spinach RUBISCO) was digested within 15 s. Data support the hypothesis that food allergens must be sufficiently stable to reach the intestinal mucosa where absorption and sensitization can occur. It is concluded that stability to digestion is an important parameter which distinguishes food allergens from non-allergens

↩

[51] - Fu TJ, Abbott UR, Hatzos C. Digestibility of food allergens and nonallergenic proteins in simulated gastric fluid and simulated intestinal fluid-a comparative study. J Agric Food Chem 2002;50:7154-7160

Information on the comparative digestibility of food allergens and nonallergenic proteins is crucial when stability to digestion is to be used as a criterion to assess the allergenic potential of novel proteins. In this work, we compared the digestive stability of a number of food allergens and proteins of unproven allergenicity and examined whether allergens possess a higher stability than nonallergenic proteins of similar cellular functions, and whether there is a correlation between protein digestibility and allergenicity. The stability of groups of storage proteins, plant lectins, contractile proteins, and enzymes, both allergens and proteins with unproven allergenicity, in a standard simulated gastric fluid and a standard simulated intestinal fluid was measured. Food allergens were not necessarily more resistant to digestion than nonallergenic proteins. There was not a clear relationship between digestibility measured in vitro and protein allergenicity.

↩

[52] - Ofori-Anti AO, Ariyarathna H, Chen L, Lee HL, Pramod SN, Goodman RE. Establishing objective detection limits for the pepsin digestion assay used in the assessment of genetically modified foods. Regul Toxicol Pharmacol 2008;52:94-103

RATIONALE: Guidelines for assessing the potential allergenicity of genetically modified (GM) organisms recommend testing the digestibility of the introduced protein by pepsin. Previous studies detailed the digestion procedure but have not described a simple objective measurement of the extent of digestion nor evaluated the impact of variation in pepsin activity. METHODS: Samples of eight proteins were digested by pepsin at pH 1.2 and 2.0 using standard conditions (10,000 U of pepsin activity per mg test protein) as well as 5000 and 20,000 units per mg of test protein. An independent digestion assay of hemoglobin was used to verify pepsin activity for each assay. Digestion was stopped in timed samples between 0.5 and 60 min. Digestion samples and undigested protein (10% and 100%) were separated by SDS-PAGE. Residual stained protein bands were measured by image analysis. RESULTS: The differences in pH and pepsin concentration only had minor effects on digestion of intermediately stable proteins: concanavalin A, ovalbumin, and lysozyme, but not on rapidly digested or stable proteins. CONCLUSIONS: Verification of pepsin activity and measurement of an objective endpoint of digestion (e.g. (90%) should provide more comparable results for the safety assessment of novel food proteins.

↩

[53] - Thomas K, Aalbers M, Bannon GA, Bartels M, Dearman RJ, Esdaile DJ, et al. A multi-laboratory evaluation of a common in vitro pepsin digestion assay protocol used in assessing the safety of novel proteins. Regul Toxicol Pharmacol 2004;39:87-98

Rationale. Evaluation of the potential allergenicity of proteins derived from genetically modified foods has involved a weight of evidence approach that incorporates an evaluation of protein digestibility in pepsin. Currently, there is no standardized protocol to assess the digestibility of proteins using simulated gastric fluid. Potential variations in assay parameters include: pH, pepsin purity, pepsin to target protein ratio, target protein purity, and method of detection. The objective was to assess the digestibility of a common set of proteins in nine independent laboratories to determine the reproducibility of the assay when performed using a common protocol. Methods. A single lot of each test protein and pepsin was obtained and distributed to each laboratory. The test proteins consisted of Ara h 2 (a peanut conglutin-like protein), beta-lactoglobulin, bovine serum albumin, concanavalin A, horseradish peroxidase, ovalbumin, ovomucoid, phosphinothricin acetyltransferase, ribulose diphosphate carboxylase, and soybean trypsin inhibitor. A ratio of 10U of pepsin activity/microg test protein was selected for all tests (3:1 pepsin to protein, w:w). Digestions were performed at pH 1.2 and 2.0, with sampling at 0.5, 2, 5, 10, 20, 30, and 60min. Protein digestibility was assessed from stained gels following SDS-PAGE of digestion samples and controls. Results. Results were relatively consistent across laboratories for the full-length proteins. The identification of proteolytic fragments was less consistent, being affected by different fixation and staining methods. Overall, assay pH did not influence the time to disappearance of the full-length protein or protein fragments, however, results across laboratories were more consistent at pH 1.2 (91% agreement) than pH 2.0 (77%). Conclusions. These data demonstrate that this common protocol for evaluating the in vitro digestibility of proteins is reproducible and yields consistent results when performed using the same proteins at different laboratories.

↩

[54] - Urisu A, Yamada K, Tokuda R, Ando H, Wada E, Kondo Y, et al. Clinical significance of IgE-binding activity to enzymatic digests of ovomucoid in the diagnosis and the prediction of the outgrowing of egg white hypersensitivity. Int Arch Allergy Immunol 1999;120:192-198

BACKGROUND: We frequently encounter subjects without overt symptoms despite high IgE antibodies to egg white and its components. The measurements of these antibodies are not necessarily efficient for the diagnosis or the prediction of the outcome of egg allergy in children. METHODS: Specific IgE antibodies to egg white and its components, including ovomucoid, ovalbumin, ovotransferrin and lysozyme, were measured by direct RAST assays. IgE-binding activity to ovomucoid degraded by pepsin, trypsin and chymotrypsin was examined by RAST inhibition. Thirty subjects were divided into two groups with positive (n=18 mean age +/- SD = 42 +/-25 months) and negative (n=12 mean age +/- SD = 48 +/-31 months) oral challenge tests with egg white antigens. The individuals with positive results to the first challenge tests were given the second provocation tests at mean intervals of 32 months. IgE-binding activity of the sera collected on the first challenge to these ovomucoid fragments was compared between subjects with positive and negative reactions to the follow-up challenge tests. RESULTS: There were no significant differences in IgE antibody titers to egg white and its components between the positive and negative groups at the first and the second challenge tests. IgE-binding activity to ovomucoid digests after treatments with pepsin (p = 0.000008) and trypsin (p=0.037), except chymotrypsin (p=0.062), were significantly higher in subjects with positive challenge tests than in those with negative results. The difference was most remarkable in the IgE-binding to pepsin digests the average concentrations (mean - SD and mean + SD) needed for 50% RAST inhibition in the positive group and in the negative group were 2.6 microg/ml (0.3 and 25) and 94.2 microg/ml (24.7 and 358.7), respectively. A significant difference was still observed in the inhibition tests using filtrates of pepsin digests with a membrane with MW 10,000 (p=0.014) and 3,000 (p=0.042) of cutoff. The concentration (mean= 0.8, mean - SD=0.2, mean + SD=3.4 microg/ml) of pepsin-treated ovomucoid required for 50% RAST inhibition in the subjects with positive second challenge results was significantly (p=0.033) lower than that (mean=6.8, mean-SD=0.6, mean + SD=73.9) of the negative group. CONCLUSION: IgE-binding activity to pepsin-digested ovomucoid was of diagnostic value to distinguish the challenge-positive subjects from the negative subjects. Subjects with high IgE-binding activity to pepsin-treated ovomucoid are unlikely to outgrow egg white allergy.

↩

[55] - Takagi K, Teshima R, Okunuki H, Itoh S, Kawasaki N, Kawanishi T, et al. Kinetic Analysis of Pepsin Digestion of Chicken Egg White Ovomucoid and Allergenic Potential of Pepsin Fragments. Int Arch Allergy Immunol 2005;136:23-32

BACKGROUND: The allergenic potential of chicken egg white ovomucoid (OVM) is thought to depend on its stability to heat treatment and digestion. Pepsin-digested fragments have been speculated to continue to exert an allergenic potential. OVM was digested in simulated gastric fluid (SGF) to examine the reactivity of the resulting fragments to IgE in sera from allergic patients . METHODS: OVM was digested in SGF and subjected to SDS-PAGE. The detected fragments were then subjected to N-terminal sequencing and liquid chromatography/mass spectrometry/mass spectrometry analysis to confirm the cleavage sites and partial amino acid sequences. The reactivity of the fragments to IgE antibodies in serum samples from patients allergic to egg white was then determined using Western blotting (n=24) . RESULTS: The rate of OVM digestion depended on the pepsin/OVM ratio in the SGF. OVM was first cleaved near the end of the first domain, and the resulting fragments were then further digested into smaller fragments. In the Western blot analysis, 93% of the OVM-reactive sera also bound to the 23.5- to 28.5-kDa fragments, and 21% reacted with the smaller 7- and 4.5-kDa fragments . CONCLUSION: When the digestion of OVM in SGF was kinetically analyzed, 21% of the examined patients retained their IgE-binding capacity to the small 4.5-kDa fragment. Patients with a positive reaction to this small peptide fragment were thought to be unlikely to outgrow their egg white allergy. The combination of SGF-digestibility studies and human IgE-binding experiments seems to be useful for the elucidation and diagnosis of the allergenic potential of OVM.

↩

[56] - Fu TJ, Abbott UR, Hatzos C. Digestibility of food allergens and nonallergenic proteins in simulated gastric fluid and simulated intestinal fluid-a comparative study. J Agric Food Chem 2002;50:7154-7160

Information on the comparative digestibility of food allergens and nonallergenic proteins is crucial when stability to digestion is to be used as a criterion to assess the allergenic potential of novel proteins. In this work, we compared the digestive stability of a number of food allergens and proteins of unproven allergenicity and examined whether allergens possess a higher stability than nonallergenic proteins of similar cellular functions, and whether there is a correlation between protein digestibility and allergenicity. The stability of groups of storage proteins, plant lectins, contractile proteins, and enzymes, both allergens and proteins with unproven allergenicity, in a standard simulated gastric fluid and a standard simulated intestinal fluid was measured. Food allergens were not necessarily more resistant to digestion than nonallergenic proteins. There was not a clear relationship between digestibility measured in vitro and protein allergenicity.

↩

[57] - Takagi K, Teshima R, Okunuki H, Itoh S, Kawasaki N, Kawanishi T, et al. Kinetic Analysis of Pepsin Digestion of Chicken Egg White Ovomucoid and Allergenic Potential of Pepsin Fragments. Int Arch Allergy Immunol 2005;136:23-32

BACKGROUND: The allergenic potential of chicken egg white ovomucoid (OVM) is thought to depend on its stability to heat treatment and digestion. Pepsin-digested fragments have been speculated to continue to exert an allergenic potential. OVM was digested in simulated gastric fluid (SGF) to examine the reactivity of the resulting fragments to IgE in sera from allergic patients . METHODS: OVM was digested in SGF and subjected to SDS-PAGE. The detected fragments were then subjected to N-terminal sequencing and liquid chromatography/mass spectrometry/mass spectrometry analysis to confirm the cleavage sites and partial amino acid sequences. The reactivity of the fragments to IgE antibodies in serum samples from patients allergic to egg white was then determined using Western blotting (n=24) . RESULTS: The rate of OVM digestion depended on the pepsin/OVM ratio in the SGF. OVM was first cleaved near the end of the first domain, and the resulting fragments were then further digested into smaller fragments. In the Western blot analysis, 93% of the OVM-reactive sera also bound to the 23.5- to 28.5-kDa fragments, and 21% reacted with the smaller 7- and 4.5-kDa fragments . CONCLUSION: When the digestion of OVM in SGF was kinetically analyzed, 21% of the examined patients retained their IgE-binding capacity to the small 4.5-kDa fragment. Patients with a positive reaction to this small peptide fragment were thought to be unlikely to outgrow their egg white allergy. The combination of SGF-digestibility studies and human IgE-binding experiments seems to be useful for the elucidation and diagnosis of the allergenic potential of OVM.

↩

[58] - Yoshino K, Sakai K, Mizuha Y, Shimizuike A, Yamamoto S. Peptic digestibility of raw and heat-coagulated hen's egg white proteins at acidic pH range. Int J Food Sci Nutr 2004;55:635-640

Allergenicity in food proteins is generally dependent on their heat stability and resistance to digestive enzymes together with the presence of IgE-recognizing epitopes on the molecules. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting, we assessed peptic digestibility of raw and heat-coagulated hen's egg white proteins at acidic pH range (1.5-4.0). Ovalbumin in raw egg white was slightly digested by pepsin at pH 1.5 and pH 2.0, and was almost resistant to the enzyme at pH 2.5 and over, which was altered in heat-coagulated egg white at the pH range from 1.5 to 2.5 where the protein was well digestive against the enzyme. Peptic digestibility of ovomucoid in raw egg white was good at the pH range from 1.5 to 2.5, but almost non-existent at pH 3.0 and over where the improvement of the digestibility of the protein was not found even in heat-coagulated egg white. As the stomach in new born infants shows a low amount of secretary pepsin and an out of optimum pH of peptic activity, low digestibility of ovalbumin and ovomucoid in raw and heat-coagulated egg white at over pH 3.0 is supposed to be responsible for their allergenicity and delayed outgrowth from hen's egg allergy in patients with delayed maturation of stomach functions

↩

[59] - Fiocchi A, Bouygue GR, Sarratud T, Terracciano L, Martelli A, Restani P. Clinical tolerance of processed foods. Ann Allergy Asthma Immunol 2004;93(5 Suppl. 3):S38-S46

OBJECTIVE: To review the effects of technological processing on selected foods of relevance to childhood allergy from the viewpoints of reduced allergenicity, contamination of processed foods by allergens introduced during processing, and ad hoc technologies to produce reduced hypoallergenic products. DATA SOURCES: We searched the literature (PubMed/MEDLINE) for articles published between January 1994 and April 2004 using the following keywords: food allergy AND process* OR heat* OR cooking OR toleran*. STUDY SELECTION: We drew on our collective clinical and biological experience to restrict retrieved studies to those of more frequent relevance to a hospital allergy practice. RESULTS: Comparatively few clinical studies address the modification of allergenicity of food through cooking or processing. Dairy foods are largely unaffected by processing and may be contaminated by, or themselves become, hidden allergens. Hypoallergenic formulas based on milk, soy, or rice and homogenized beef are successful applications of allergenicity reduction via technological processing. Egg, fish, condiments, and vegetables all carry heat-resistant allergens and should also be considered contaminants. Cereals and bakery products are generally well tolerated, but their allergenicity may be enhanced by processing; the case of rice is still open. Peanut allergens are stable, and the evidence is scant that thermal processing affects the allergenicity of soybean and soy hydrolysates. The debate is ongoing about the tolerance of vegetable oils. CONCLUSIONS: It is too early to systematize clinical studies based on single procedures. Processing affects antigenicity, but this does not always translate into safety recommendations. Industrial processing is liable to contamination, and monitoring and labeling are industry priorities. Clinicians should evaluate foods by as complete a workup as possible before recommending processed foods.

↩

[60] - Seo JH, Kim JH, Lee JW, Yoo YC, Kim MR, Park KS, et al. Ovalbumin modified by gamma irradiation alters its immunological functions and allergic responses. Int Immunopharmacol 2007;7:464-472

It is well known that gamma (gamma)-ray irradiation results in the alteration of biological function of bioactive materials such as proteins, saccharides and lipids. In this study the effect of gamma-irradiation on the chemical and immunological property of an allergen, ovalbumin (OVA), was investigated. Irradiation of more than 10 kGy resulted in the alteration of the structure of OVA. However, OVA treated with 10 kGy irradiation (10 kGy-OVA), but not 100 kGy-OVA, fully maintained immunological reactivity to a monoclonal antibody specific to the intact allergen (clone 14). Mice immunized with 10 kGy- as well as 100 kGy-OVA showed significantly lower antibody response to the allergen than those with intact OVA in a gamma-ray dosage-dependent manner. Especially immunization of both 10 kGy- and 100 kGy-OVA induced a significant decrease of OVA-specific IgE. Splenocytes of mice immunized with irradiated OVA showed a significant reduction in OVA-specific T cell proliferation and the secretion of Th1-type (IFN-gamma and IL-2) and Th2-type cytokines (IL-4 and IL-6). The expression of T cell activation markers such as CD25 and CD44 was also down-regulated in T cells of mice immunized with irradiated OVAs. These results suggest that gamma-ray irradiation of OVA suppress humoral and cellular immune responses specific to the allergen OVA, and the modification method with gamma-irradiation may be available for the control of allergy.

↩

[61] - Lopez-Exposito I, Chicon R, Belloque J, Recio I, Alonso E, Lopez-Fandino R. Changes in the Ovalbumin Proteolysis Profile by High Pressure and Its Effect on IgG and IgE Binding. J Agric Food Chem 2008;56:11809-11816

Egg proteins are responsible for one of the most common forms of food allergy, especially in children, and one of the major allergens is ovalbumin (OVA). With the aim to examine the potential of high pressure to enhance the enzymatic hydrolysis of OVA and modify its immunoreactivity, the protein was proteolyzed with pepsin under high-pressure conditions (400 MPa). Characterization of the hydrolysates and peptide identification was performed by reversed-phase high-performance liquid chromatography-tandem mass spectrometry (RP-HPLC-MS/MS). The antigenicity (binding to IgG) and binding to IgE, using the sera of patients with specific IgE to OVA, were also assessed. The results showed that, upon treatment with pepsin at 400 MPa, all of the intact protein was removed in minutes, leading to the production of hydrolysates with lower antigenicity than those produced in hours at atmospheric pressure. However, the exposure of new target residues only partially facilitated the removal of allergenic epitopes, because the hydrolysates retained residual IgG- and IgE-binding properties as a result of the accumulation of large and hydrophobic peptides during the initial stages of hydrolysis. These peptides disappeared at later stages of proteolysis, although reactivity toward IgG and IgE was not completely abolished. Some fragments identified in the hydrolysates (such as Leu(124)-Phe(134), Ile(178)-Ala(187), Leu(242)-Leu(252), Gly(251)-Ile(259), Lys(322)-Gly(343), Phe(358)-Phe(366), and Phe(378)-Pro(385)) carried previously identified IgE-binding epitopes. Because some of the peptides found, such as Phe(358)-Phe(366), probably contain only one binding site for IgE, the possibility to use high pressure to tailor hydrolysates that contain mostly peptides with only one IgE-binding site, which may help the immune system to tolerate egg proteins, is suggested.

↩

[62] - Lopez-Exposito I, Chicon R, Belloque J, Recio I, Alonso E, Lopez-Fandino R. Changes in the Ovalbumin Proteolysis Profile by High Pressure and Its Effect on IgG and IgE Binding. J Agric Food Chem 2008;56:11809-11816

Egg proteins are responsible for one of the most common forms of food allergy, especially in children, and one of the major allergens is ovalbumin (OVA). With the aim to examine the potential of high pressure to enhance the enzymatic hydrolysis of OVA and modify its immunoreactivity, the protein was proteolyzed with pepsin under high-pressure conditions (400 MPa). Characterization of the hydrolysates and peptide identification was performed by reversed-phase high-performance liquid chromatography-tandem mass spectrometry (RP-HPLC-MS/MS). The antigenicity (binding to IgG) and binding to IgE, using the sera of patients with specific IgE to OVA, were also assessed. The results showed that, upon treatment with pepsin at 400 MPa, all of the intact protein was removed in minutes, leading to the production of hydrolysates with lower antigenicity than those produced in hours at atmospheric pressure. However, the exposure of new target residues only partially facilitated the removal of allergenic epitopes, because the hydrolysates retained residual IgG- and IgE-binding properties as a result of the accumulation of large and hydrophobic peptides during the initial stages of hydrolysis. These peptides disappeared at later stages of proteolysis, although reactivity toward IgG and IgE was not completely abolished. Some fragments identified in the hydrolysates (such as Leu(124)-Phe(134), Ile(178)-Ala(187), Leu(242)-Leu(252), Gly(251)-Ile(259), Lys(322)-Gly(343), Phe(358)-Phe(366), and Phe(378)-Pro(385)) carried previously identified IgE-binding epitopes. Because some of the peptides found, such as Phe(358)-Phe(366), probably contain only one binding site for IgE, the possibility to use high pressure to tailor hydrolysates that contain mostly peptides with only one IgE-binding site, which may help the immune system to tolerate egg proteins, is suggested.

↩

[63] - Hildebrandt S, Kratzin HD, Schaller R, Fritsché R, Steinhart H, Paschke A. In Vitro Determination of the Allergenic Potential of Technologically Altered Hen's Egg. J Agric Food Chem 2008;56:1727-1733

Hen's egg allergy represents one of the most common and severe IgE-mediated reactions to food in infants and young children. It persists, however, in many cases also lifelong. Therefore, the aim of this study was the detailed analysis of a technological process used to reduce the allergenic potential of hen's egg. The investigation focused on the pasteurized egg as starting material, intermediate, and final products of a nine-step manufacturing process performed for use of eggs in convenience products appropriate for allergic individuals. The steps consisted of a combination of various heat treatments and enzymatic hydrolyses. The alterations were controlled by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, enzyme allergosorbent test (EAST) inhibition, and mass spectrometry. Thereby it could be demonstrated that the allergenic potential of the raw material was reduced from step to step, and despite the known stability against heat and proteolysis of certain egg proteins, the total allergenic potential was finally below (1)/ 100 that of the starting material without a significant change in texture and flavor as evaluated in various products.

↩

[64] - Enrique E, Cistero Bahima A, Alonso R, San Miguel MM. Egg protein: a hidden allergen in candies. Ann Allergy Asthma Immunol 2000;84:636

↩

[65] - Weber P, Steinhart H, Paschke A. Investigation of the Allergenic Potential of Wines Fined with Various Proteinogenic Fining Agents by ELISA. J Agric Food Chem 2007;55:3127-3133

Hidden allergens are a common problem in food safety that has been known for many years. This is why the European Parliament adopted Directive 2003/89/EC amending 2000/13/EC. In addition to specific ingredients, Directive 2003/89/EC also requests the declaration of specific products that were used in the production and could be a risk for allergic individuals. This also includes the declaration of fining agents and lysozyme used in wines. In fact, it could be assumed that fining agents would be almost completely removed during the manufacturing process; however, until now there has been no necessity to analyze wine for these fining agents. By applying enzyme-linked immunosorbent assay (ELISA), residuals of fining agent proteins and the stabilizer lysozyme were investigated in various German wines. The results showed no detectable amounts of fining agents in wines, except for dried egg white and lysozyme, both derived from hen's egg white. For those products, adverse reactions against treated wines could not be excluded. Keywords: Wine; fining agent; allergen; allergy; isinglass; lysozyme; food allergy; hidden allergens; immunoassay; fish gelatin; hen's egg protein; ovalbumin; casein.

↩

[66] - Lifrani A, Dos Santos J, Dubarry M, Rautureau M, Blachier F, Tome D. Development of Animal Models and Sandwich-ELISA Tests to Detect the Allergenicity and Antigenicity of Fining Agent Residues in Wines. J Agric Food Chem 2009;57:525-534

Food allergy can cause food-related anaphylaxis. Food allergen labeling is the principal means of protecting sensitized individuals. This motivated European Directive 2003/89 on the labeling of ingredients or additives that could trigger adverse reactions, which has been in effect since 2005. During this study, we developed animal models with allergy to ovalbumin, caseinate, and isinglass in order to be able to detect fining agent residues that could induce anaphylactic reactions in sensitized mice. The second aim of the study was to design sandwich ELISA tests specific to each fining agent in order to detect their residue antigenicity, both during wine processing and in commercially available bottled wines. Sensitized mice and sandwich ELISA methods were established to test a vast panel of wines. The results showed that although they were positive to our highly sensitive sandwich-ELISA tests, some commercially available wines are not allergenic in sensitized mice. Commercially available bottled wines made using standardized processes, fining, maturation, and filtration, do not therefore represent any risk of anaphylactic reactions in sensitized mice.

↩

[67] - Rolland JM, Apostolou E, Deckert K, de Leon MP, Douglass JA, Glaspole IN, et al. Potential food allergens in wine: Double-blind, placebo-controlled trial and basophil activation analysis. Nutrition 2006;22:882-888

OBJECTIVE: Recent Australian and international legislation requires labeling of wines made by using the potentially allergenic food proteins casein, milk, egg white, or isinglass (fish-derived) where "there is a detectable residual processing aid." We investigated whether wines fined using these proteins or non-grape-derived tannins (tree-nut derived) can provoke significant clinical allergic reactions (anaphylaxis) in patients with confirmed immunoglobulin E-mediated relevant food allergy. METHODS: A double-blind, placebo-controlled trial was performed to determine whether allergic reactions followed consumption of Australian commercial wines fined using one or more of the legislation-targeted food proteins. In addition, allergenicity of a larger panel of these wines was evaluated by blood basophil activation. RESULTS: No anaphylaxis was induced by wine consumption. Three mild clinical reactions to protein-fined wine and two mild reactions to unfined wine occurred, but there was no statistically significant difference in reaction parameters between subject groups or between processing aids. No pattern of basophil activation correlated with wine type, processing aid, or subject group. CONCLUSION: Wines fined with egg white, isinglass, or non-grape-derived tannins present an extremely low risk of anaphylaxis to fish-, egg-, or peanut-allergic consumers. Although consumption of milk protein-fined wine did not induce anaphylaxis, there were insufficient subjects to determine statistically whether wines fined with milk proteins present a risk to the very rare milk-allergic consumers. In summary, the observed lack of anaphylaxis and basophil activation induced by wines made using the legislation-targeted food proteins according to good manufacturing practice suggests negligible residual food allergens in these wines.

↩

[68] - Kirschner S, Belloni B, Kugler C, Ring J, Brockow K. Allergenicity of Wine Containing Processing Aids: A Double-Blind, Placebo-Controlled Food Challenge. J Investig Allergol Clin Immunol 2009;19:210-217

BACKGROUND: The European Union requires allergenic food ingredients to appear on labels in order to protect allergic consumers . OBJECTIVE: To determine whether traces of egg-, milk-, and fish-derived processing aids used in winemaking might elicit clinical reactions in food-allergic patients . METHODS: Five German wines were fined with a high dose of egg albumin, lysozyme, milk casein, fish gelatin, or isinglass, and filtered. Fourteen adults with allergy to egg (n = 5), milk (n = 5), or fish (n = 4) were included. Skin prick tests were performed with fining agents, and fined and unfined wines. All patients underwent double-blind placebo-controlled food challenges with fined and unfined wines . RESULTS: Skin prick tests were positive to hen's egg (n = 5), ovalbumin (n = 5), lysozyme (n = 4), cow's milk (n = 5), casein (n = 4), and cod (n = 3), but not to isinglass or fish gelatin (n = 0). Positive skin prick test results were observed for wines fined with albumin (n = 3), lysozyme (n = 2), casein (n = 1), gelatin (n = 0), and isinglass (n = 3), and for unfined wines (n = 1-2 in each patient group), with no significant differences between groups. Seventy-five percent of skin test-positive patients had specific immunoglobulin E to other allergens present in wine (eg, carbohydrates). The provocation test revealed no reactions to fined or unfined wines . CONCLUSIONS: Although concentrated fining agents containing ovalbumin, lysozyme, and casein were allergenic in the skin prick test, no patient reacted adversely in the provocation test to fined wine. Wines treated with fining agents at commercial concentrations appear not to present a risk to allergic individuals when filtered,

↩

[69] - Moneret-Vautrin DA, Lemerdy P. VPP des prick tests aux aliments natifs: vers un diagnostic absolu ? Alim'Inter 2006;11:228-232

↩

[70] - Celik-Bilgili S, Mehl A, Verstege A, Staden U, Nocon M, Beyer K, et al. The predictive value of specific immunoglobulin E levels in serum for the outcome of oral food challenges. Clin Exp Allergy 2005;35:268-273

Summary Background Specific serum IgE is considered as one of the important diagnostic measures in the diagnostic work-up of food allergy. Objective To evaluate the role of specific serum IgE in predicting the outcome of oral food challenges, and to determine threshold concentrations of specific serum IgE that could render double-blind, placebo-controlled food challenges unnecessary. Methods In 501 children (median age 13 months), 992 controlled oral challenges were performed with cow's milk (CM), hen's egg (HE), wheat and soy. 440/501 (88%) children suffered from atopic dermatitis. For all children, specific IgE concentrations in serum were determined. Sensitivity, specificity, positive and negative predictive values, receiver operator characteristics-curves as well as predictive decision points were calculated. Results Four hundred and forty-five out of 992 oral food challenges with allergens were assessed as positive. Sensitivity of specific serum IgE was 97% for HE, 83% for CM, 69% for soy, and 79% for wheat. Specificity was 51% for HE, 53% for CM, 50% for soy, and 38% for wheat. Calculating 90%, 95% and 99% predicted probabilities using logistic regression revealed predictive decision points of 6.3, 12.6, and 59.2 kU/L for HE, respectively. Subdividing our children in those of below or above 1 year of age resulted in a markedly different predicted probability for HE. For CM, only the 90% predicted probability (88.8 kU/L) could be calculated. No decision points could be determined for CM, wheat and soy. Conclusion In general, specific serum IgE levels showed a correlation with the outcome of positive oral food challenges for CM and HE. Meaningful predictive decision points can be calculated for HE, which may help to avoid oral food challenges in some cases. However, data need to be ascertained for each allergen separately. Furthermore, the age of the patient population under investigation must also be taken into account.

↩

[71] - Sampson HA, Ho DG. Relationship between food-specific IgE concentrations and the risk of positive food challenges in children and adolescents. J Allergy Clin Immunol 1997;100:444-451

"BACKGROUND: The double-blind, placebo-controlled food challenge (DBPCFC) is the ""gold standard"" for diagnosis of food hypersensitivity. Skin prick tests and RASTs are sensitive indicators of food-specific IgE antibodies but poor predictors of clinical reactivity. Previous studies suggested that high concentrations of food-specific IgE antibody were predictive of food-induced clinical symptoms. Because the CAP System FEIA (Pharmacia Diagnostics, Uppsala, Sweden) provides a quantitative assessment of allergen-specific IgE antibody, this study was undertaken to determine the potential utility of the CAP System FEIA in diagnosis of IgE-mediated food hypersensitivity . METHODS: Sera from 196 patients with food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by CAP System FEIA. Sera were randomly selected from 300 stored samples of children and adolescents who had been evaluated by history, skin prick tests, and DBPCFCs. The study population was highly atopic; all patients had atopic dermatitis, and approximately 50% had asthma and allergic rhinitis at the time of initial evaluation. The performance characteristics of the CAP System FEIA were compared with those of skin prick tests and the outcome of DBPCFCs or ""convincing"" histories of anaphylactic reactions . RESULTS: The prevalence of specific food allergies in the study population varied from 22% for wheat to 73% for egg. Allergy to egg, milk, peanut, and soy accounted for 87% of confirmed reactions. The performance characteristics of skin prick tests and CAP System FEIA (egg, milk, peanut, fish) were comparable, with excellent sensitivity and negative predictive accuracy but poor specificity and positive predictive accuracy. The performance characteristics of the CAP System FEIA for soy and wheat were poor. For egg, milk, peanut, and fish allergy, diagnostic levels of IgE, which could predict clinical reactivity in this population with greater than 95% certainty, were identified: egg, 6 kilounits of allergen-specific IgE per liter (kU[A]/L); milk, 32 kU(A)/L; peanut, 15 kU(A)/L; and fish, 20 kU(A)/L . CONCLUSIONS: When compared with the outcome of DBPCFCs, results of CAP System FEIA are generally comparable to those of skin prick tests in predicting symptomatic food hypersensitivity. Furthermore, by measuring the concentrations of food-specific IgE antibodies with the CAP System FEIA, it is possible to identify a subset of patients who are highly likely (>95%) to experience clinical reactions to egg, milk, peanut, or fish. This could eliminate the need to perform DBPCFCs in a significant number of patients suspected of having IgE-mediated food allergy."

↩

[72] - Boyano-Martinez T, Garcia-Ara C, Diaz-Pena JM, Munoz FM, Garcia Sanchez G, Martin-Esteban M. Validity of specific IgE antibodies in children with egg allergy. Clin Exp Allergy 2001;31:1464-1469

BACKGROUND: The demonstration of specific IgE antibodies to egg supports the existence of allergy to this food, but a correct diagnosis can only be obtained after a challenge test. Several studies have assessed different cut-off points in the level of these antibodies as predictors of clinical reactivity . OBJECTIVE: Validation of the specific IgE antibodies measured by the CAP System Fluorescence enzyme immunoassay (FEIA) technique in the diagnosis of egg allergy in children under 2 years of age . METHODS: A prospective study of 81 children with suspected egg allergy was performed. Specific IgE antibodies was quantified for egg white, egg yolk, ovoalbumin and ovomucoid. The diagnostic challenge test was carried out following the previously established criteria. The validity of the specific IgE antibodies was analysed using children with a negative diagnostic challenge test as control group . RESULTS: The prevalence of egg allergy in the group studied was 79% and egg white was the allergen that showed the greatest diagnostic efficacy. The sensitivity and positive predictive value of the prick test and of the CAP to egg white were excellent and the specificity and the negative predictive value had lower values. A level of > or = 0.35 KU(A)/L for specific IgE antibodies to egg white predicted the existence of reaction in 94% of the cases . CONCLUSIONS: Quantification of the specific IgE antibodies to egg white is useful in the diagnosis of egg allergy. In children under 2 years of age with a background of immediate hypersensitivity after egg ingestion and presence of specific IgE antibodies to egg white of > or = 0.35 KU(A)/L, diagnostic challenge test is not necessary to establish the diagnosis of allergy to this food.

↩

[73] - Sporik R, Hill DJ, Hosking CS. Specificity of allergen skin testing in predicting positive open food challenges to milk, egg and peanut in children. Clin Exp Allergy 2000;30:1540-1546

BACKGROUND: The specificity of allergen skin prick testing to diagnose clinically relevant food allergy is controversial . OBJECTIVES: To determine the specificity of the allergen weal diameter to correctly identify children who react on formal open food challenges . METHODS: Over a 9-year period children referred to a tertiary allergy clinic for the evaluation of suspected food allergy were prospectively studied. Allergen skin prick testing to cow milk, egg white and peanut extracts (Dome-Hollister-Stier, Spokane, WA, USA) was undertaken using a lancet technique. All children underwent open food challenges to the relevant food(s) in a hospital clinic. Challenges were classified as positive, if objective signs were seen; negative, if the child could tolerate normal quantities of the food, daily, for one week; or inconclusive if none of the former criteria were met . RESULTS: Five hundred and fifty-five challenges were undertaken in 467 children: 339 challenges to cow milk, 121 to egg, and 95 to peanut. Fifty-five percentage of challenges were positive, 37% negative, and 8% inconclusive. For each food it was possible to identify a skin weal diameter at, and above, which negative reactions did not occur: cow milk, 8 mm; egg, 7 mm; peanut, 8 mm. In contrast, positive reactions could occur with a skin wheal diameter of 0 mm . CONCLUSIONS: In this high risk referral population it was possible to define skin weal diameters to egg, milk and peanut above which open oral food challenges were positive (100% specificity). By utilizing these measurements the need for formal food challenges can be reduced.

↩

[74] - Villard-Truc F, Gomez SA, Deschildre A, Rancé F. Test de provocation par voie orale aux aliments chez l'enfant. Quand, pour qui et comment? 2- Sélection des patients. Rev Fr Allergol Immunol Clin 2006;46:610-624

↩

[75] - Monti G, Muratore MC, Peltran A, Bonfante G, Silvestro L, Oggero R, et al. High incidence of adverse reactions to egg challenge on first known exposure in young atopic dermatitis children: predictive value of skin prick test and radioallergosorbent test to egg proteins. Clin Exp Allergy 2002;32:1515-1519

↩

[76] - Verstege A, Mehl A, Rolinck-Werninghaus C, Staden U, Nocon M, Beyer K, et al. The predictive value of the skin prick test weal size for the outcome of oral food challenges. Clin Exp Allergy 2005;35:1220-1226

BACKGROUND: The skin prick test (SPT) is regarded as an important diagnostic measure in the diagnostic work-up of food allergy. Objective To evaluate the diagnostic capacity of the SPT in predicting the outcome of oral food challenges, and to determine decision points for the weal size and the skin index (SI) that could render double-blind, placebo-controlled food challenges unnecessary . METHODS: In 385 children (median age 22 months), 735 controlled oral challenges were performed with cow's milk (CM), hen's egg (HE), wheat and soy. Three hundred and thirty-six of 385 (87%) children suffered from atopic dermatitis. SPT was performed in all children. Diagnostic capacity, receiver-operator characteristics (ROC) curves and predictive decision points were calculated for the mean weal size and the calculated SI . RESULTS: Three hundred and twelve of 735 (43%) oral food challenges were assessed to be positive. Calculation of 95% and 99% predicted probabilities using logistic regression revealed predictive decision points of 13.0 and 17.8 mm for HE, and 12.5 and 17.3 mm for CM, respectively. However, using the SI, the corresponding cut-off levels were 2.6 and 3.7, respectively, for HE, and 2.7 and 3.7 for CM. For wheat, 95% and 99% decision points of 2.2 and 3.0 were found in children below 1 year of age . CONCLUSION: Predictive decision points for a positive outcome of food challenges can be calculated for HE and CM using weal size and SI. They may help to avoid oral food challenges.

↩

[77] - Diéguez MC, Cerecedo I, Muriel A, Zamora J, Sánchez-Cano M, De la Hoz B. Skin prick test predictive value on the outcome of a first known egg exposure in milk-allergic children. Pediatr Allergy Immunol 2008;19:319-324

Children with milk allergy have higher incidence of other food allergies, especially egg allergy. The objective of this study was to ascertain the accuracy of the prick test in children with IgE-mediated milk allergy for diagnosing egg allergy. Children under the age of 1 yr who came consecutively to Allergy Department 2003-05, and were diagnosed with IgE-mediated milk allergy were selected for this study. Egg introduction was completely avoided until the age of 14 months when clinical history, skin prick tests (SPT), specific-IgE antibodies determination and egg challenge test were performed. One hundred and four milk-allergic children were included. At least one positive prick test to any egg allergen was found in 65 out of the 104 (62.5%). Thirty-eight (36.5%) were allergic to egg proteins as well. Prick tests with egg white and ovomucoid (OVM) had the best diagnostic performances showing the largest areas under the receiver operating characteristic curve. The optimal diagnosis cut-off point was 6 mm for egg white and 5 mm for OVM. The positive likelihood ratios for these cut-off points were: 2.95 (95% CI: 1.74-4.99) for egg white prick test, and 20 (95% CI: 2.9-143.7) for OVM prick test. Children with specific IgE-mediated cow's milk allergy must be closely followed as a risk group for egg allergy. Early diagnosis is necessary and the SPT has shown itself to be a very useful tool for diagnosing immediate IgE reactions to egg on first known exposure.

↩

[78] - Moneret-Vautrin DA, Lemerdy P. VPP des prick tests aux aliments natifs: vers un diagnostic absolu ? Alim'Inter 2006;11:228-232

↩

[79] - Diéguez MC, Cerecedo I, Muriel A, Zamora J, Sánchez-Cano M, De la Hoz B. Skin prick test predictive value on the outcome of a first known egg exposure in milk-allergic children. Pediatr Allergy Immunol 2008;19:319-324

Children with milk allergy have higher incidence of other food allergies, especially egg allergy. The objective of this study was to ascertain the accuracy of the prick test in children with IgE-mediated milk allergy for diagnosing egg allergy. Children under the age of 1 yr who came consecutively to Allergy Department 2003-05, and were diagnosed with IgE-mediated milk allergy were selected for this study. Egg introduction was completely avoided until the age of 14 months when clinical history, skin prick tests (SPT), specific-IgE antibodies determination and egg challenge test were performed. One hundred and four milk-allergic children were included. At least one positive prick test to any egg allergen was found in 65 out of the 104 (62.5%). Thirty-eight (36.5%) were allergic to egg proteins as well. Prick tests with egg white and ovomucoid (OVM) had the best diagnostic performances showing the largest areas under the receiver operating characteristic curve. The optimal diagnosis cut-off point was 6 mm for egg white and 5 mm for OVM. The positive likelihood ratios for these cut-off points were: 2.95 (95% CI: 1.74-4.99) for egg white prick test, and 20 (95% CI: 2.9-143.7) for OVM prick test. Children with specific IgE-mediated cow's milk allergy must be closely followed as a risk group for egg allergy. Early diagnosis is necessary and the SPT has shown itself to be a very useful tool for diagnosing immediate IgE reactions to egg on first known exposure.

↩

[80] - Turjanmaa K, Darsow U, Niggemann B, Rancé F, Vanto T, Werfel T. EAACI/GA2LEN Position paper: Present status of the atopy patch test. Allergy 2006;61:1377-1384

A number of scientific reports have been published on patch tests with protein allergens performed on patients with atopic eczema (AE). Evaluation of eczematous skin lesions with an atopy patch test (APT) can be used as a diagnostic tool in characterizing patients with aeroallergen- and food-triggered AE. Indications for testing with APT, choice of allergens (aeroallergens and foods), test materials and technique, including present knowledge on sensitivity and specificity, are reviewed on the basis of available literature. This position paper also points out the need for future research on the clinical use of the APT.

↩

[81] - Devillers ACA, de Waard-van der Spek FB, Mulder PGH, Oranje AP. Delayed- and immediate-type reactions in the atopy patch test with food allergens in young children with atopic dermatitis. Pediatr Allergy Immunol 2008;19:53-58

↩

[82] - Mehl A, Rolinck-Werninghaus C, Staden U, Verstege A, Wahn U, Beyer K, et al. The atopy patch test in the diagnostic workup of suspected food-related symptoms in children. J Allergy Clin Immunol 2006;118:923-929

BACKGROUND: There is an increasing need to develop test instruments that make oral food challenges superfluous . OBJECTIVE: We sought to study the utility of atopy patch tests (APTs) in the diagnostic workup of food allergy . METHODS: We investigated 437 children (median age, 13 months; 90% with atopic dermatitis) referred for evaluation of suspected food allergy. Specific serum IgE (sIgE) measurements, skin prick tests (SPTs), APTs, and controlled oral food challenges were performed . RESULTS: We analyzed 873 oral challenges with cow's milk, hen's egg, wheat, and/or soy. One thousand seven hundred single APTs were performed. As a single parameter, the APTs showed the best specificity compared with sIgE measurements, SPTs, or both. Combining the APT with either the SPT or sIgE measurement resulted in improved sensitivity and specificity. Decision points for sIgE measurement and for the SPT showed lower values when combined with a positive APT result. Correctly bypassing an oral food challenge with combined testing, including APTs, only between 0.5% and 7% (99% predicted probability) and between 6% and 14% (using 95% predicted probability) of children would fulfill the criteria for avoiding an oral food challenge . CONCLUSION: Although the predictive capacity of the APT is improved when combined with sIgE measurement or the SPT, oral food challenges become superfluous in only 0.5% to 14% of study patients. In addition, the APT is time consuming and demands a highly experienced test evaluator. CLINICAL IMPLICATIONS: For daily clinical practice, the APT adds only a small predictive value to the standard SPT and sIgE measurement in the diagnostic workup of suspected food-related symptoms in our study population.

↩

[83] - Caffarelli C, Cavagni G, Giordano S, Stapane I, Rossi C. Relationship between oral challenges with previously uningested egg and egg-specific IgE antibodies and skin prick tests in infants with food allergy. J Allergy Clin Immunol 1995;95:1215-1220

BACKGROUND: Positive skin prick test (SPT) and RAST reactions to egg that had never previously been ingested have been observed in infants with food allergy. The likelihood of having clinical hypersensitivity reactions when egg is first ingested and the predictive value of SPT and RAST remain to be elucidated. OBJECTIVE: We investigated the relationship between egg-specific IgE antibodies and positive SPT reaction to egg, and the development of clinical hypersensitivity on the first exposure, in infants with food allergy. METHODS: The patient group consisted of 21 infants with food allergy and positive SPT and/or RAST reaction to egg, which they had never previously ingested; the control group of 12 infants had food allergy and negative test results. All subjects underwent double-blind placebo-controlled food challenges with egg. RESULTS: Thirteen of 21 patients (61%) and one of 12 control subjects (8%) had positive reactions to challenges (p < 0.01). Thirteen positive reactions to challenges (93%) elicited immediate symptoms. Late-onset eczema occurred in two children. SPT results showed a high sensitivity (0.92) and negative predictive accuracy (0.92), whereas specificity (0.57) and positive predictive accuracy (0.61) were poor. RAST did not have any diagnostic advantage over SPT. CONCLUSIONS: In infants with food allergy SPT with egg may be helpful in predicting which patients will react to the first exposure.

↩

[84] - Sampson HA, Ho DG. Relationship between food-specific IgE concentrations and the risk of positive food challenges in children and adolescents. J Allergy Clin Immunol 1997;100:444-451

"BACKGROUND: The double-blind, placebo-controlled food challenge (DBPCFC) is the ""gold standard"" for diagnosis of food hypersensitivity. Skin prick tests and RASTs are sensitive indicators of food-specific IgE antibodies but poor predictors of clinical reactivity. Previous studies suggested that high concentrations of food-specific IgE antibody were predictive of food-induced clinical symptoms. Because the CAP System FEIA (Pharmacia Diagnostics, Uppsala, Sweden) provides a quantitative assessment of allergen-specific IgE antibody, this study was undertaken to determine the potential utility of the CAP System FEIA in diagnosis of IgE-mediated food hypersensitivity . METHODS: Sera from 196 patients with food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by CAP System FEIA. Sera were randomly selected from 300 stored samples of children and adolescents who had been evaluated by history, skin prick tests, and DBPCFCs. The study population was highly atopic; all patients had atopic dermatitis, and approximately 50% had asthma and allergic rhinitis at the time of initial evaluation. The performance characteristics of the CAP System FEIA were compared with those of skin prick tests and the outcome of DBPCFCs or ""convincing"" histories of anaphylactic reactions . RESULTS: The prevalence of specific food allergies in the study population varied from 22% for wheat to 73% for egg. Allergy to egg, milk, peanut, and soy accounted for 87% of confirmed reactions. The performance characteristics of skin prick tests and CAP System FEIA (egg, milk, peanut, fish) were comparable, with excellent sensitivity and negative predictive accuracy but poor specificity and positive predictive accuracy. The performance characteristics of the CAP System FEIA for soy and wheat were poor. For egg, milk, peanut, and fish allergy, diagnostic levels of IgE, which could predict clinical reactivity in this population with greater than 95% certainty, were identified: egg, 6 kilounits of allergen-specific IgE per liter (kU[A]/L); milk, 32 kU(A)/L; peanut, 15 kU(A)/L; and fish, 20 kU(A)/L . CONCLUSIONS: When compared with the outcome of DBPCFCs, results of CAP System FEIA are generally comparable to those of skin prick tests in predicting symptomatic food hypersensitivity. Furthermore, by measuring the concentrations of food-specific IgE antibodies with the CAP System FEIA, it is possible to identify a subset of patients who are highly likely (>95%) to experience clinical reactions to egg, milk, peanut, or fish. This could eliminate the need to perform DBPCFCs in a significant number of patients suspected of having IgE-mediated food allergy."

↩

[85] - Boyano-Martinez T, Garcia-Ara C, Diaz-Pena JM, Munoz FM, Garcia Sanchez G, Martin-Esteban M. Validity of specific IgE antibodies in children with egg allergy. Clin Exp Allergy 2001;31:1464-1469

BACKGROUND: The demonstration of specific IgE antibodies to egg supports the existence of allergy to this food, but a correct diagnosis can only be obtained after a challenge test. Several studies have assessed different cut-off points in the level of these antibodies as predictors of clinical reactivity . OBJECTIVE: Validation of the specific IgE antibodies measured by the CAP System Fluorescence enzyme immunoassay (FEIA) technique in the diagnosis of egg allergy in children under 2 years of age . METHODS: A prospective study of 81 children with suspected egg allergy was performed. Specific IgE antibodies was quantified for egg white, egg yolk, ovoalbumin and ovomucoid. The diagnostic challenge test was carried out following the previously established criteria. The validity of the specific IgE antibodies was analysed using children with a negative diagnostic challenge test as control group . RESULTS: The prevalence of egg allergy in the group studied was 79% and egg white was the allergen that showed the greatest diagnostic efficacy. The sensitivity and positive predictive value of the prick test and of the CAP to egg white were excellent and the specificity and the negative predictive value had lower values. A level of > or = 0.35 KU(A)/L for specific IgE antibodies to egg white predicted the existence of reaction in 94% of the cases . CONCLUSIONS: Quantification of the specific IgE antibodies to egg white is useful in the diagnosis of egg allergy. In children under 2 years of age with a background of immediate hypersensitivity after egg ingestion and presence of specific IgE antibodies to egg white of > or = 0.35 KU(A)/L, diagnostic challenge test is not necessary to establish the diagnosis of allergy to this food.

↩

[86] - Roehr CC, Reibel S, Ziegert M, Sommerfeld C, Wahn U, Niggemann B. Atopy patch tests, together with determination of IgE levels, reduce the need for need for oral food challenges in children with atopic dermatitis. J Allergy Clin Immunol 2001;107:548-553

BACKGROUND: Atopic dermatitis is commonly associated with food allergy. In addition to skin prick tests (SPTs) and measurements of specific IgE levels, the atopy patch test (APT) has recently been introduced into the diagnostic procedure for food allergy . OBJECTIVE: Our aim was to evaluate whether a combination of allergologic tests could improve the prognostic value of the individual tests for positive food challenge results. We hypothesized that the combination of a positive APT result plus proof of specific IgE, a positive SPT result, or both would render double-blind, placebo-controlled, food challenges unnecessary . METHODS: One hundred seventy-three double-blind, placebo-controlled, food challenges were performed in 98 children (median age, 13 months) with atopic dermatitis. All children were subjected to SPTs, APTs, and determination of specific IgE. Sensitivity, specificity, and positive and negative predictive values were calculated . RESULTS: Ninety-five (55%) of 173 oral provocations were assessed as positive. For evaluating suspected cow's milk (CM) allergy, the APT was the best single predictive test (positive predictive value [PPV], 95%), and the combination of a positive APT result with evidence of specific IgE or an APT result together with a positive skin prick test response optimized the PPV to 100%. For hen's egg (HE) allergy, the APT was also the best single predictive test (PPV, 94%). The combination of 2 or more tests did not exceed the APT's predictive value. In both CM and HE challenges, the predictability of oral challenges depended on the level of specific IgE. For wheat allergy, the APT proved to be the most reliable test, and the PPV of 94% could not be improved by a combination with other allergologic tests . CONCLUSION: The combination of positive APT results and measurement of levels of specific IgE (CM, > or = 0.35 kU/L; HE, > or = 17.5 kU/L) makes double-blind, placebo-controlled, food challenges superfluous for suspected CM and HE allergy.

↩

[87] - Monti G, Muratore MC, Peltran A, Bonfante G, Silvestro L, Oggero R, et al. High incidence of adverse reactions to egg challenge on first known exposure in young atopic dermatitis children: predictive value of skin prick test and radioallergosorbent test to egg proteins. Clin Exp Allergy 2002;32:1515-1519

↩

[88] - Rancé F, Fargeot-Espaliat A, Rittié JL, Micheau P, Morelle K, Abbal M. Valeur diagnostique du dosage des IgE spécifiques dirigées contre le blanc et le jaune d'œuf dans le diagnostic de l'allergie alimentaire à l'œuf de poule chez l'enfant. Rev Fr Allergol Immunol Clin 2003;43:369-372

L'objectif de l'étude est de définir les valeurs d'IgE spécifiques pour confirmer le diagnostic d'allergie à l'oeuf de poule avec une probabilité proche de 100 %. L'étude est conduite chez 185 enfants suspects d'allergie alimentaire vus consécutivement à l'hôpital des enfants de Toulouse. Un premier groupe est composé de 100 enfants dont l'allergie à l'oeuf est prouvée par un test de provocation par voie orale positif. Ces enfants sont comparés à un deuxième groupe de 85 enfants non allergiques à l'oeuf mais allergiques à un autre aliment, le plus souvent l'arachide. Tous les enfants ont bénéficié d'une exploration similaire : analyse clinique, prick test natif pour l'oeuf de poule (blanc et jaune), dosage des IgE sériques spécifiques pour le blanc et le jaune d'oeuf avec la technique Pharmacia Cap System, et test de provocation par voie orale. L'âge moyen des enfants est de 2,1 ans avec des extrêmes de 8 mois à 15 ans. Le diamètre moyen du prick test blanc d'oeuf est de 11,3 mm (extrêmes 0 à 25 mm) pour le groupe 1 et de 5,5 mm pour le groupe 2, p = 0,00001. La médiane des IgE spécifiques du blanc d'oeuf est plus élevée chez les allergiques à l'oeuf (22,5 kUA/L vs 0,76, p = 0,000001), comme la médiane des IgE jaune d'oeuf (6 kUA/L vs 0,35, p = 0,0001). Une concentration d'IgE blanc d'oeuf supérieure ou égale à 7,5 kUA/L est associée à une valeur prédictive positive de 100 % (valeur prédictive négative 68 %). Une concentration d'IgE jaune d'oeuf supérieure ou égale à 5,5 kUA/L est associée à une valeur prédictive positive de 100 % (valeur prédictive négative 52 %). Conclusion. - Notre étude objective une meilleure sensibilité des IgE blanc d'oeuf et une meilleure spécificité des IgE jaune d'oeuf. Les deux mesures sont utiles pour le diagnostic de l'allergie à l'oeuf de poule chez l'enfant. Des IgE blanc d'oeuf supérieures ou égales à 7,5 kUA/L et des IgE jaune d'oeuf supérieures ou égales à 5,5 kUA/L permettent de porter le diagnostic d'allergie à l'oeuf avec une probabilité proche de 100 %.

↩

[89] - Ricci G, Capelli M, Miniero R, Menna G, Zannarini L, Dillon P, et al. A comparison of different allergometric tests, skin prick test, Pharmacia UniCAP and ADVIA Centaur, for diagnosis of allergic diseases in children. Allergy 2003;58:38-45

BACKGROUND: The diagnosis of allergic disease is performed by skin prick tests (SPT) or through the demonstration of specific IgE in a blood sample via an in vitro test. The measurement of IgE concentration against allergens provides critical information in clinical allergy. Standardized and reproducible methods contribute to the quality of diagnosis and treatment of allergic disease . METHODS: In this study we evaluated the performance of a new specific IgE method, developed by ALK-Abellò for Bayer Diagnostics to run on their ADVIA Centaur immunoassay system. One hundred and fifty-one children with allergic diseases (both food and inhalant allergies) were tested for specific IgE (sIgE) via SPT and in vitro tests (UniCAP system, Pharmacia, and ADVIA Centaur immunoassay system, Bayer Diagnostics) and the test results were correlated with the clinical data . RESULTS: Statistical analysis revealed no significant difference between the two in vitro tests compared with clinical history. The sensitivities and specificities are similar, but the UniCAP system method has higher sensitivity. In the children with cow's milk allergy, the UniCAP system has sensitivity of 91% and specificity of 70%; the ADVIA Centaur immunoassay has sensitivity of 82% and specificity of 74%. In hen's egg allergy, UniCAP system has 94% sensitivity and 64% specificity, and the ADVIA Centaur system has 88% sensitivity and 52% specificity. In inhalant allergies, the two methods show statistically similar performances for both grass pollen allergies (UniCAP sensitivity 100%, specificity 73%; ADVIA Centaur sensitivity 95%, specificity 79%) and in the dust mites allergies (UniCAP sensitivity 91%, specificity 62%; ADVIA Centaur sensitivity 86%, specificity 64%). In cat allergies, the systems showed equivalent results (UniCAP sensitivity 100%, specificity 71%; ADVIA Centaur sensitivity 100%, specificity 70%). Using the UniCAP system, the geometric mean of sIgE values in children with clinical allergy is significantly higher than in sensitized ones. The ADVIA Centaur system shows a similar trend with the exclusion of cow's milk and Dermatophagoides farinae allergens. With this last method the mean value of sIgE is higher in sensitized than in symptomatic children . CONCLUSION: The new ADVIA Centaur method compares favorably with the results obtained on the UniCAP system. If other studies continue to confirm this data, then the advantages are numerous: the use of only a small quantity of serum (25 micro l per allergen), rapid turnaround time, minimal hands-on time, and no interference from IgG.

↩

[90] - Ando H, Movérare R, Kondo Y, Tsuge I, Tanaka A, Borres MP, et al. Utility of ovomucoid-specific IgE concentrations in predicting symptomatic egg allergy. J Allergy Clin Immunol 2008;122:583-588

Grass pollens are one of the most important airborne allergen sources worldwide. About 20 species from five subfamilies are considered to be the most frequent causes of grass pollen allergy, and the allergenic relationships among them closely follow their phylogenetic relationships. The allergic immune response to pollen of several grass species has been studied extensively over more than three decades. Eleven groups of allergens have been identified and described, in most cases from more than one species. The allergens range from 6 to 60 kD in apparent molecular weight and display a variety of physicochemical properties and structures. The most complete set of allergens has so far been isolated and cloned from Phleum pratense (timothy grass) pollen. Based on the prevalence of IgE antibody recognition among grass pollen-sensitized individuals, several allergens qualify as major, but members of two groups, groups 1 and 5, have been shown to dominate the immune response to grass pollen extract. Isoform variation has been detected in members of several of the allergen groups, which in some cases can be linked to observed genetic differences. N-linked glycosylation occurs in members of at least three groups. Carbohydrate- reactive IgE antibodies have been attributed to grass pollen sensitization and found to cross-react with glycan structures from other allergen sources, particularly vegetable foods. Another cause of extensive cross-reactivity are the group 12 allergens (profilins), which belong to a family of proteins highly conserved throughout the plant kingdom and present in all tissues. Members of eight allergen groups have been cloned and expressed as recombinant proteins capable of specific IgE binding. This development now allows diagnostic dissection of the immune response to grass pollen with potential benefits for specific immunotherapy.

↩

[91] - Norgaard A, Bindslev-Jensen C. Egg and milk allergy in adults. Diagnosis and characterization. Allergy 1992;47:503-509

Nineteen adult patients representing a total of 24 medical histories of immediate adverse reactions to egg or cows' milk underwent 1) standardized questioning about signs/symptoms occurring less than 2 h after ingestion of egg or milk, 2) skin prick test, RAST and histamine release test, and 3) titrated, oral, double-blind, placebo-controlled challenge (DBPCFC) with fresh egg or milk. Eleven medical histories (46%) were confirmed by DBPCFC in 10 patients (53%). All DBPCFC-positive patients experienced gastrointestinal symptoms, and in 80% of the patients, gastrointestinal symptoms were accompanied by respiratory or skin symptoms. Threshold doses varied between 50 mg and 250 g, with 4 patients presenting objective signs following 5 g or less. DBPCFC-positive patients reported significantly more symptoms and had a significantly higher number of positive tests than had DBPCFC-negative patients. None of the tests were in significant concordance with DBPCFC, although RAST showed a sensitivity of 100%. Thus, DBPCFC cannot be substituted in the diagnosis of milk and egg allergy in adults. The use of titrated, fresh foods in DBPCFC proved to be a safe and well-controlled procedure.

↩

[92] - Norgaard A, Bindslev-Jensen C, Skov PS, Poulsen LK. Specific serum IgE in the diagnosis of egg and milk allergy in adults. Allergy 1995;50:636-647

Levels of specific serum IgE to cow's milk, whole hen's egg, egg white, and egg yolk were compared to the outcome of double-blind, placebo-controlled food challenge (DBPCFC) with fresh egg and/or milk in 21 adults with a case history of immediate hypersensitivity to egg and/or milk. Specific serum IgE was measured by four different commercially available tests and by an inhouse Maxisorp RAST using freshly prepared food extracts. Sensitivities and negative predictive accuracies were generally high with egg white and milk, but low with egg yolk. Specificities and positive predictive accuracies were low for all allergens and tests. Changing the cutoff levels did not improve the ability of the tests to predict clinical allergy. Among commercially available test allergens, egg white gave the most consistent results in levels and class scores, and the highest degree of concordance with DBPCFC, whereas egg yolk and milk varied more. Applying freshly prepared food extracts in Maxisorp RAST did not improve diagnostic value. Measuring specific serum IgE levels in control subjects tolerant to egg/milk showed that false positive reactions occurred frequently among patients with another food allergy and atopic dermatitis, whereas most tests were likely to be negative in pollen-allergic and nonallergic volunteers. In conclusion, specific IgE measurements with egg white and milk were useful for exclusion of symptomatic hypersensitivity to egg and milk in patients with a positive history, whereas DBPCFC is still mandatory in patients with positive history and positive test. Measuring egg-yolk-specific IgE or using freshly prepared food extracts for specific IgE measurements added no further diagnostic information. The rate of clinically insignificant positive test results seems to be influenced by the prevalence of other food allergies and/or atopic dermatitis in the population under study.

↩

[93] - Ispano M, Colafrancesco M, Ansaloni R, Vighi G, Ortolani C. Comparison of the results of skin prick tests, CAP System and ENEA System in the diagnosis of food allergy. Highlights Food Allergy 1996;32:181-186

↩

[94] - Sampson HA, Ho DG. Relationship between food-specific IgE concentrations and the risk of positive food challenges in children and adolescents. J Allergy Clin Immunol 1997;100:444-451

"BACKGROUND: The double-blind, placebo-controlled food challenge (DBPCFC) is the ""gold standard"" for diagnosis of food hypersensitivity. Skin prick tests and RASTs are sensitive indicators of food-specific IgE antibodies but poor predictors of clinical reactivity. Previous studies suggested that high concentrations of food-specific IgE antibody were predictive of food-induced clinical symptoms. Because the CAP System FEIA (Pharmacia Diagnostics, Uppsala, Sweden) provides a quantitative assessment of allergen-specific IgE antibody, this study was undertaken to determine the potential utility of the CAP System FEIA in diagnosis of IgE-mediated food hypersensitivity . METHODS: Sera from 196 patients with food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by CAP System FEIA. Sera were randomly selected from 300 stored samples of children and adolescents who had been evaluated by history, skin prick tests, and DBPCFCs. The study population was highly atopic; all patients had atopic dermatitis, and approximately 50% had asthma and allergic rhinitis at the time of initial evaluation. The performance characteristics of the CAP System FEIA were compared with those of skin prick tests and the outcome of DBPCFCs or ""convincing"" histories of anaphylactic reactions . RESULTS: The prevalence of specific food allergies in the study population varied from 22% for wheat to 73% for egg. Allergy to egg, milk, peanut, and soy accounted for 87% of confirmed reactions. The performance characteristics of skin prick tests and CAP System FEIA (egg, milk, peanut, fish) were comparable, with excellent sensitivity and negative predictive accuracy but poor specificity and positive predictive accuracy. The performance characteristics of the CAP System FEIA for soy and wheat were poor. For egg, milk, peanut, and fish allergy, diagnostic levels of IgE, which could predict clinical reactivity in this population with greater than 95% certainty, were identified: egg, 6 kilounits of allergen-specific IgE per liter (kU[A]/L); milk, 32 kU(A)/L; peanut, 15 kU(A)/L; and fish, 20 kU(A)/L . CONCLUSIONS: When compared with the outcome of DBPCFCs, results of CAP System FEIA are generally comparable to those of skin prick tests in predicting symptomatic food hypersensitivity. Furthermore, by measuring the concentrations of food-specific IgE antibodies with the CAP System FEIA, it is possible to identify a subset of patients who are highly likely (>95%) to experience clinical reactions to egg, milk, peanut, or fish. This could eliminate the need to perform DBPCFCs in a significant number of patients suspected of having IgE-mediated food allergy."

↩

[95] - Rancé F, Fargeot-Espaliat A, Rittié JL, Micheau P, Morelle K, Abbal M. Valeur diagnostique du dosage des IgE spécifiques dirigées contre le blanc et le jaune d'œuf dans le diagnostic de l'allergie alimentaire à l'œuf de poule chez l'enfant. Rev Fr Allergol Immunol Clin 2003;43:369-372

L'objectif de l'étude est de définir les valeurs d'IgE spécifiques pour confirmer le diagnostic d'allergie à l'oeuf de poule avec une probabilité proche de 100 %. L'étude est conduite chez 185 enfants suspects d'allergie alimentaire vus consécutivement à l'hôpital des enfants de Toulouse. Un premier groupe est composé de 100 enfants dont l'allergie à l'oeuf est prouvée par un test de provocation par voie orale positif. Ces enfants sont comparés à un deuxième groupe de 85 enfants non allergiques à l'oeuf mais allergiques à un autre aliment, le plus souvent l'arachide. Tous les enfants ont bénéficié d'une exploration similaire : analyse clinique, prick test natif pour l'oeuf de poule (blanc et jaune), dosage des IgE sériques spécifiques pour le blanc et le jaune d'oeuf avec la technique Pharmacia Cap System, et test de provocation par voie orale. L'âge moyen des enfants est de 2,1 ans avec des extrêmes de 8 mois à 15 ans. Le diamètre moyen du prick test blanc d'oeuf est de 11,3 mm (extrêmes 0 à 25 mm) pour le groupe 1 et de 5,5 mm pour le groupe 2, p = 0,00001. La médiane des IgE spécifiques du blanc d'oeuf est plus élevée chez les allergiques à l'oeuf (22,5 kUA/L vs 0,76, p = 0,000001), comme la médiane des IgE jaune d'oeuf (6 kUA/L vs 0,35, p = 0,0001). Une concentration d'IgE blanc d'oeuf supérieure ou égale à 7,5 kUA/L est associée à une valeur prédictive positive de 100 % (valeur prédictive négative 68 %). Une concentration d'IgE jaune d'oeuf supérieure ou égale à 5,5 kUA/L est associée à une valeur prédictive positive de 100 % (valeur prédictive négative 52 %). Conclusion. - Notre étude objective une meilleure sensibilité des IgE blanc d'oeuf et une meilleure spécificité des IgE jaune d'oeuf. Les deux mesures sont utiles pour le diagnostic de l'allergie à l'oeuf de poule chez l'enfant. Des IgE blanc d'oeuf supérieures ou égales à 7,5 kUA/L et des IgE jaune d'oeuf supérieures ou égales à 5,5 kUA/L permettent de porter le diagnostic d'allergie à l'oeuf avec une probabilité proche de 100 %.

↩

[96] - Malandain H. Quelle valeur clinique accorder aux résultats chiffrés des dosages d'IgE spécifiques ? Rev Fr Allergol Immunol Clin 2002;42:798-805

Les explorations in vitro en allergie ont recours principalement aux dosages des IgE « spécifiques » (IgE-S). Ces tests sont souvent dénommés Rast et leurs résultats exprimés à la fois en unités semi-quantitatives, les classes, et en valeurs chiffrées, les kU/l. Ce double système a-t-il obscurci la valeur et donc l'utilité clinique des résultats chiffrés des tests in vitro ? Les dosages sanguins sont-ils en soi suffisants pour poser un diagnostic d'allergie ou pour prédire une future allergie ? Les courbes de risque récemment proposées et fondées sur des études de populations peuvent-elles améliorer l'efficacité des tests in vitro de ce point de vue ? Cet article analyse ces questions sur la base d'arguments théoriques et expérimentaux. Il en ressort que les résultats chiffrés des dosages d'IgE-S ne traduisent pas fidèlement l'expression clinique du patient et ne doivent donc être interprétés qu'avec le reste du dossier du patient. Les courbes de risque ne sont pas une meilleure solution car elles ajoutent à ces limitations des IgE-S un autre problème : ces courbes sont fortement dépendantes des caractéristiques des cohortes de sujets qui ont servi à les calculer (âge, environnement, etc...). Aussi, l'intérêt de ces courbes pour un patient donné est très limité en pratique quotidienne.

↩

[97] - Guenel E, de Boissieu D, Dupont C. Tests de provocation orale à l'œuf: analyse rétrospective sur un an. Rev Fr Allergol Immunol Clin 2004;44:132

↩

[98] - Komata T, Söderström L, Borres MP, Tachimoto H, Ebisawa M. The predictive relationship of food-specific serum IgE concentrations to challenge outcomes for egg and milk varies by patient age. J Allergy Clin Immunol 2007;119:1272-1274

↩

[99] - Celik-Bilgili S, Mehl A, Verstege A, Staden U, Nocon M, Beyer K, et al. The predictive value of specific immunoglobulin E levels in serum for the outcome of oral food challenges. Clin Exp Allergy 2005;35:268-273

Summary Background Specific serum IgE is considered as one of the important diagnostic measures in the diagnostic work-up of food allergy. Objective To evaluate the role of specific serum IgE in predicting the outcome of oral food challenges, and to determine threshold concentrations of specific serum IgE that could render double-blind, placebo-controlled food challenges unnecessary. Methods In 501 children (median age 13 months), 992 controlled oral challenges were performed with cow's milk (CM), hen's egg (HE), wheat and soy. 440/501 (88%) children suffered from atopic dermatitis. For all children, specific IgE concentrations in serum were determined. Sensitivity, specificity, positive and negative predictive values, receiver operator characteristics-curves as well as predictive decision points were calculated. Results Four hundred and forty-five out of 992 oral food challenges with allergens were assessed as positive. Sensitivity of specific serum IgE was 97% for HE, 83% for CM, 69% for soy, and 79% for wheat. Specificity was 51% for HE, 53% for CM, 50% for soy, and 38% for wheat. Calculating 90%, 95% and 99% predicted probabilities using logistic regression revealed predictive decision points of 6.3, 12.6, and 59.2 kU/L for HE, respectively. Subdividing our children in those of below or above 1 year of age resulted in a markedly different predicted probability for HE. For CM, only the 90% predicted probability (88.8 kU/L) could be calculated. No decision points could be determined for CM, wheat and soy. Conclusion In general, specific serum IgE levels showed a correlation with the outcome of positive oral food challenges for CM and HE. Meaningful predictive decision points can be calculated for HE, which may help to avoid oral food challenges in some cases. However, data need to be ascertained for each allergen separately. Furthermore, the age of the patient population under investigation must also be taken into account.

↩

[100] - Sporik R, Hill DJ, Hosking CS. Specificity of allergen skin testing in predicting positive open food challenges to milk, egg and peanut in children. Clin Exp Allergy 2000;30:1540-1546

BACKGROUND: The specificity of allergen skin prick testing to diagnose clinically relevant food allergy is controversial . OBJECTIVES: To determine the specificity of the allergen weal diameter to correctly identify children who react on formal open food challenges . METHODS: Over a 9-year period children referred to a tertiary allergy clinic for the evaluation of suspected food allergy were prospectively studied. Allergen skin prick testing to cow milk, egg white and peanut extracts (Dome-Hollister-Stier, Spokane, WA, USA) was undertaken using a lancet technique. All children underwent open food challenges to the relevant food(s) in a hospital clinic. Challenges were classified as positive, if objective signs were seen; negative, if the child could tolerate normal quantities of the food, daily, for one week; or inconclusive if none of the former criteria were met . RESULTS: Five hundred and fifty-five challenges were undertaken in 467 children: 339 challenges to cow milk, 121 to egg, and 95 to peanut. Fifty-five percentage of challenges were positive, 37% negative, and 8% inconclusive. For each food it was possible to identify a skin weal diameter at, and above, which negative reactions did not occur: cow milk, 8 mm; egg, 7 mm; peanut, 8 mm. In contrast, positive reactions could occur with a skin wheal diameter of 0 mm . CONCLUSIONS: In this high risk referral population it was possible to define skin weal diameters to egg, milk and peanut above which open oral food challenges were positive (100% specificity). By utilizing these measurements the need for formal food challenges can be reduced.

↩

[101] - Ott H, Baron JM, Heise R, Ocklenburg C, Stanzel S, Merk HF, et al. Clinical usefulness of microarray-based IgE detection in children with suspected food allergy. Allergy 2008;63:1521-1528

BACKGROUND: Component-resolved diagnostics using microarray technology has recently been introduced into clinical allergology, but its applicability in children with food allergy has hardly been investigated so far. The aim of this study was to evaluate the utility of microarray-based IgE detection in the diagnostic workup of food allergy and to compare this new diagnostic tool with established methods of allergen-specific IgE detection . METHODS: We investigated 130 infants and children with suspected allergy to cow's milk (CM) or hen's egg (HE). Serum IgE measurements, skin prick tests, allergen microarray assays and controlled oral food challenges with HE and CM were performed . RESULTS: We analyzed 145 oral challenges that served as reference parameters for assay performance assessment. On this basis, the panel of microarrayed allergen components was shown to represent a comprehensive repertoire of clinically relevant CM and HE proteins. Additionally, the implemented CM and HE components respectively sufficed for equivalent test performance as compared to the corresponding fluorescence enzyme immunoassay extract and skin testing. However, component-resolved diagnostics for HE and CM allergy did not make oral food challenges superfluous. Clinical IgE decision points predicting positive oral food challenges could be calculated for both in vitro test methods . CONCLUSIONS: Allergen microarrays provide a new tool to diagnose symptomatic CM and HE allergy. They show performance characteristics comparable to the current diagnostic tests and may be indicated in small children in whom only small blood volumes are obtainable. However, they are not capable of replacing double-blind, placebo-controlled food challenges in most cases.

↩

[102] - Sampson HA. Food allergy – accurately identifying clinical reactivity. Allergy 2005;60(Suppl. 79):19-24

Up to 25% of adults believe that they or their children are afflicted with a food allergy. However, the actual prevalence of food allergy is much lower: approximately 6-8% of children suffer from food allergy during their first 3 years of life, and many children then develop clinical tolerance. Food allergy encompasses a whole spectrum of disorders, with symptoms that may be cutaneous, gastrointestinal or respiratory in nature. Food disorders also differ according to the extent that they are immunoglobulin E (IgE)-mediated. Skin-prick testing is often used to identify food sensitization, although double-blind, placebo-controlled food challenge (DBPCFC) tests remain the gold standard for diagnosis. Recent evidence suggests that quantitative IgE measurements can predict the outcome of DBPCFC tests and can replace about half of all oral food challenges. When an extensive medical history is obtained in combination with IgE quantification, even fewer patients may require formal food challenges. It has also become possible to map the IgE-binding regions of many major food allergens. This may help to identify children with persistent food allergy, as opposed to those who may develop clinical tolerance. In future, microarray technology may enable physicians to screen patients for a large number of food proteins and epitopes, using just a few drops of blood.

↩

[103] - Villard-Truc F, Gomez SA, Deschildre A, Rancé F. Test de provocation par voie orale aux aliments chez l'enfant. Quand, pour qui et comment? 2- Sélection des patients. Rev Fr Allergol Immunol Clin 2006;46:610-624

↩

[104] - Moneret-Vautrin DA, Lemerdy P. VPP des prick tests aux aliments natifs: vers un diagnostic absolu ? Alim'Inter 2006;11:228-232

↩

[105] - Foucard T, Lilja G. Monitoring of IgE-mediated food allergy in childhood. Acta Paediatr 2004;93:730-733

Testing for IgE-mediated allergy is performed to reach or refute a suspected allergy. But a positive test does only indicate sensitization and not necessarily clinical allergy. A diagnostic challenge procedure is therefore necessary. Also, in the phase of tolerance development a challenge is needed as clinical tolerance is reached before allergen-specific IgE antibodies have disappeared. During recent years, an increasing interest has been given to the possibility of using the concentration of specific IgE and the size of the skin prick test wheal to tell the optimal time to do a challenge without exposing the child to a risk of a severe reaction. Conclusion: Algorithms on when to do and when not to do a food challenge may be useful but should be used with great caution. Reasonable consideration should be paid to the severity of previous reactions and the kind of allergen involved.

↩

[106] - Eigenmann PA. Are specific immunoglobulin E titres reliable for prediction of food allergy ? Clin Exp Allergy 2005;35:247-249

↩

[107] - Niggemann B, Beyer K. Diagnostic pitfalls in food allergy in children. Allergy 2005;60:104-107

Currently, the diagnostic work-up of suspected food allergy includes skin prick tests, the measurement of food specific immunoglobulin E (IgE), and the atopy patch test, and double-blind, placebo-controlled food challenges. However, all of these methods, even double-blind, placebo-controlled food challenges (DBPCFC), may sometimes be misleading. This overview describes several pitfalls for standard diagnostic methods such as problems with irritative skin reactions mimicking IgE-mediated symptoms, the problem of non-IgE-mediated reactions, pitfalls arising from the way foods are prepared or processed, effects of the route of exposure, the role of augmentation factors lowering the threshold value for clinical reactions, the noncomparability of specific IgE decision points, the influence of the timing of diagnostic measures. In addition, the problem of alternative diagnostic measures is discussed. In conclusion, there are several pitfalls in the diagnostic work-up of food allergy, which may be misleading for the physician. Properly performed controlled oral food challenges still represent the gold standard for implementing specific diets in food allergic individuals in order to avoid both unjustified diets, which may lead to severe impairments in growth and development, and to avoid unnecessary symptoms if an underlying food allergy is not correctly identified as a cause for the symptoms of the patient.

↩

[108] - Lemon-Mule H, Sampson HA, Sicherer SH, Shreffler WG, Noone S, Nowak-Wegrzyn A. Immunologic changes in children with egg allergy ingesting extensively heated egg. J Allergy Clin Immunol 2008;122:977-983

BACKGROUND: Prior studies have suggested that heated egg might be tolerated by some children with egg allergy . OBJECTIVE: We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated . METHODS: Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg-tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg . RESULTS: Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg-reactive subjects had larger skin test wheals and greater egg white-specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg- and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels . CONCLUSIONS: The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

↩

[109] - Diéguez MC, Cerecedo I, Muriel A, Zamora J, Sánchez-Cano M, De la Hoz B. Skin prick test predictive value on the outcome of a first known egg exposure in milk-allergic children. Pediatr Allergy Immunol 2008;19:319-324

Children with milk allergy have higher incidence of other food allergies, especially egg allergy. The objective of this study was to ascertain the accuracy of the prick test in children with IgE-mediated milk allergy for diagnosing egg allergy. Children under the age of 1 yr who came consecutively to Allergy Department 2003-05, and were diagnosed with IgE-mediated milk allergy were selected for this study. Egg introduction was completely avoided until the age of 14 months when clinical history, skin prick tests (SPT), specific-IgE antibodies determination and egg challenge test were performed. One hundred and four milk-allergic children were included. At least one positive prick test to any egg allergen was found in 65 out of the 104 (62.5%). Thirty-eight (36.5%) were allergic to egg proteins as well. Prick tests with egg white and ovomucoid (OVM) had the best diagnostic performances showing the largest areas under the receiver operating characteristic curve. The optimal diagnosis cut-off point was 6 mm for egg white and 5 mm for OVM. The positive likelihood ratios for these cut-off points were: 2.95 (95% CI: 1.74-4.99) for egg white prick test, and 20 (95% CI: 2.9-143.7) for OVM prick test. Children with specific IgE-mediated cow's milk allergy must be closely followed as a risk group for egg allergy. Early diagnosis is necessary and the SPT has shown itself to be a very useful tool for diagnosing immediate IgE reactions to egg on first known exposure.

↩

[110] - Lemon-Mule H, Sampson HA, Sicherer SH, Shreffler WG, Noone S, Nowak-Wegrzyn A. Immunologic changes in children with egg allergy ingesting extensively heated egg. J Allergy Clin Immunol 2008;122:977-983

BACKGROUND: Prior studies have suggested that heated egg might be tolerated by some children with egg allergy . OBJECTIVE: We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated . METHODS: Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg-tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg . RESULTS: Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg-reactive subjects had larger skin test wheals and greater egg white-specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg- and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels . CONCLUSIONS: The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

↩

[111] - Wolkerstorfer A, Wahn U, Kjellman NIM, Diepgen TL, De Longueville M, Oranje AP. Natural course of sensitization to cow's milk and hen's egg in childhood atopic dermatitis: ETAC Study Group. Clin Exp Allergy 2002;32:70-73

Background: Sensitization to food allergens has been implicated in the pathogenesis of atopic diseases, in particular atopic dermatitis (AD). The aim of the present paper is to investigate the natural course of sensitization to egg and to cow's milk and its relationship with the severity of AD. Methods: The placebo intentiontotreat population of the ETACTM (Early Treatment of the Atopic Child) study consisted of 397 children with AD aged 12-24 months (mean±SD: 17.2 ± 4.1 months) who were followed for 18 months. All children were examined for objective SCORing Atopic Dermatitis (SCORAD) and specific IgE amongst other, to egg and to cow's milk at inclusion and after 3, 12 and 18 months. Fifteen patients were excluded from this analysis due to major protocol violations thus leaving 382 patients in the analysed population. Results: Sensitization to egg and to cow's milk was more common in atopic children with severe AD at all timepoints. At inclusion, children sensitized to both egg and to cow's milk had the most severe AD (KruskallWallis test P = 0.007). The degree of sensitization expressed in RAST classes was significantly related to the severity of AD. Furthermore, children sensitized to egg or to cow's milk at inclusion had a higher risk of persistence of AD (84 and 67, respectively, vs. 57 in those not sensitized) and a higher objective SCORAD after 18 months followup. Conclusion: We found an association between severity of AD and sensitization to egg or to cow's milk. Moreover, sensitization to egg, and to a lesser extent cow's milk, indicates a worse outcome of AD in terms of persistence and severity of the disease.

↩

[112] - Wahn U, Warner J, Simons FER, de Benedictis FM, Diepgen TL, Naspitz CK, et al. IgE antibody responses in young children with atopic dermatitis. Pediatr Allergy Immunol 2008;19:332-336

In 2184 young children aged 13-24 months with atopic dermatitis (SCORAD 5-59) serum IgE antibodies to a standard panel of food and inhalant allergens were assayed. The frequency of positive IgE responses (>0.35 kU/l) increased with greater severity of skin disease. A significant minority of infants had levels of IgE antibody to foods to suggest they were at risk of acute reaction to those foods (7% to hen's egg, 3% to cow's milk, 4% to peanut). Our findings indicate that the frequency of positive IgE responses is related to disease severity and suggest that differences in the time course of the development of IgE responses to food, which are at maximum prevalence within the first year of life, while inhalant allergies, are still developing between 1 and 2 yr and beyond.

↩

[113] - Hill DJ, Heine RG, Hosking CS, Su JC, Varigos GA, Carlin JB. Atopic Dermatitis Is Strongly Associated With IgE-Mediated Food Allergy in Infants Attending a Dermatology Department. J Allergy Clin Immunol 2005;115(2 suppl.):S100

RATIONALE: Ten per cent of infants have atopic dermatitis (AD) of moderate severity. IgE-mediated food allergy (FA) is reportedly higher in patients referred to allergy clinics compared to dermatology cohorts METHODS: We prospectively studied the prevalence of FA in 51 consecutive infants (mean age 8.1 mo, range 5-12 mo; 39 M, 12 F) with moderate AD attending the Dermatology Department at this university-affiliated pediatric teaching hospital. A clinical history was taken and AD severity assessed by SCORAD. Skin prick testing (SPT) was performed in all infants, and in 39 food-specific IgE serum antibodies measured by CAP-system FEIA (Pharmacia, Uppsala, Sweden). FA was diagnosed if the SPT or CAP-FEIA level to cow milk, egg or peanut exceeded the reference >95%-positive predictive cut-off values for positive challenges RESULTS: The mean age of onset of AD was 12.0±7.8 weeks. Thirtyone (61%) of infants were exclusively breast-fed at onset of AD; two (4%) reported a FA reaction (egg, peanut) prior to referral. The mean SCORAD at enrolment was 17.7±11.6 (range 0-48). Based on SPT, 43/51 infants (84%, 95% confidence interval 71%-93%) had evidence of FA (cow milk 16%, egg 72%, peanut 51%); 2 additional infants initially FA-negative were FA-positive within 12 months. CAP-system FEIA identified 33/39 infants (85%, 95% confidence interval 69%-94%) with FA (cow milk 22%, egg 82%, peanut 23%). Forty-six (90%) infants were found allergic to at least one food item by either SPT or CAP system-FEIA CONCLUSIONS: AD was strongly associated with IgE-mediated FA in infants referred to a Dermatology Department

↩

[114] - Wahn U, Warner J, Simons FER, de Benedictis FM, Diepgen TL, Naspitz CK, et al. IgE antibody responses in young children with atopic dermatitis. Pediatr Allergy Immunol 2008;19:332-336

In 2184 young children aged 13-24 months with atopic dermatitis (SCORAD 5-59) serum IgE antibodies to a standard panel of food and inhalant allergens were assayed. The frequency of positive IgE responses (>0.35 kU/l) increased with greater severity of skin disease. A significant minority of infants had levels of IgE antibody to foods to suggest they were at risk of acute reaction to those foods (7% to hen's egg, 3% to cow's milk, 4% to peanut). Our findings indicate that the frequency of positive IgE responses is related to disease severity and suggest that differences in the time course of the development of IgE responses to food, which are at maximum prevalence within the first year of life, while inhalant allergies, are still developing between 1 and 2 yr and beyond.

↩

[115] - Mehl A, Verstege A, Staden U, Kulig M, Nocon M, Beyer K, et al. Utility of the ratio of food-specific IgE/total IgE in predicting symptomatic food allergy in children. Allergy 2005;60:1034-1039

BACKGROUND: Double-blind, placebo-controlled food challenges are time-consuming, expensive and not without risk to patients. Therefore, an in vitro test that could accurately diagnose food allergy would be of great value . OBJECTIVE: To evaluate the utility of the ratio of specific immunoglobulin E (IgE)/total IgE compared with specific IgE (sIgE) alone in predicting symptomatic food allergy . METHODS: We retrospectively analysed 992 controlled oral food challenges performed in 501 children (median age 13 months). The ratio of sIgE/total IgE was calculated and tested for correlation with the outcome of food challenges. Receiver operator characteristics (ROC)-curves were performed; predicted probabilities and predictive decision points were calculated . RESULTS: A significant correlation was found between the ratio and the outcome of food challenges for cow's milk (CM), hen's egg (HE), and wheat, but not for soy. The ROC and predicted probability curves as well as sensitivity and specificity of the decision points of the ratio were similar to those of sIgE levels for CM, HE and wheat . CONCLUSION: In view of the greater effort needed to determine the ratio, without benefit compared with the sIgE alone, the calculation of the ratio of sIgE/total IgE for diagnosing symptomatic food allergy offers no advantage for CM, HE, wheat or soy. For the majority of cases controlled oral food challenges still remain the method of choice.

↩

[116] - Sampson HA. Utility of food-specific IgE concentrations in predicting symptomatic food allergy. J Allergy Clin Immunol 2001;107:891-896

BACKGROUND: The double-blind, placebo-controlled food challenge is considered the gold standard for diagnosing food allergy. However, in a retrospective analysis of children and adolescents with atopic dermatitis and food allergy, discrete food-specific IgE concentrations were established that could predict clinical reactivity to egg, milk, peanut, and fish with greater than 95% certainty. OBJECTIVE: The purpose of this investigation was to determine the utility of these 95% predictive decision points in a prospective evaluation of food allergy. METHODS: Sera from 100 consecutive children and adolescents referred for evaluation of food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by using the Pharmacia CAP System FEIA. Food-specific IgE values were compared with history and the results of skin prick tests and food challenges to determine the efficacy of previously established 95% predictive decision points in identifying patients with increased probability of reacting during a specific food challenge. RESULTS: One hundred children (62% male; median age, 3.8 years; range, 0.4-14.3 years) were evaluated for food allergy. The diagnosis of food allergy was established by means of history or oral food challenge. On the basis of the previously established 95% predictive decision points for egg, milk, peanut, and fish allergy, greater than 95% of food allergies diagnosed in this prospective study were correctly identified by quantifying serum food-specific IgE concentrations. CONCLUSION: In a prospective study of children and adolescents referred for evaluation of food allergy, previously established 95% predictive decision points of food-specific IgE antibody concentrations for 4 major food allergens were effective in predicting clinical reactivity. Quantification of food-specific IgE is a useful test for diagnosing symptomatic allergy to egg, milk, peanut, and fish in the pediatric population and could eliminate the need to perform double-blind, placebo-controlled food challenges in a significant number of children.

↩

[117] - Ott H, Baron JM, Heise R, Ocklenburg C, Stanzel S, Merk HF, et al. Clinical usefulness of microarray-based IgE detection in children with suspected food allergy. Allergy 2008;63:1521-1528

BACKGROUND: Component-resolved diagnostics using microarray technology has recently been introduced into clinical allergology, but its applicability in children with food allergy has hardly been investigated so far. The aim of this study was to evaluate the utility of microarray-based IgE detection in the diagnostic workup of food allergy and to compare this new diagnostic tool with established methods of allergen-specific IgE detection . METHODS: We investigated 130 infants and children with suspected allergy to cow's milk (CM) or hen's egg (HE). Serum IgE measurements, skin prick tests, allergen microarray assays and controlled oral food challenges with HE and CM were performed . RESULTS: We analyzed 145 oral challenges that served as reference parameters for assay performance assessment. On this basis, the panel of microarrayed allergen components was shown to represent a comprehensive repertoire of clinically relevant CM and HE proteins. Additionally, the implemented CM and HE components respectively sufficed for equivalent test performance as compared to the corresponding fluorescence enzyme immunoassay extract and skin testing. However, component-resolved diagnostics for HE and CM allergy did not make oral food challenges superfluous. Clinical IgE decision points predicting positive oral food challenges could be calculated for both in vitro test methods . CONCLUSIONS: Allergen microarrays provide a new tool to diagnose symptomatic CM and HE allergy. They show performance characteristics comparable to the current diagnostic tests and may be indicated in small children in whom only small blood volumes are obtainable. However, they are not capable of replacing double-blind, placebo-controlled food challenges in most cases.

↩

[118] - Celik-Bilgili S, Mehl A, Verstege A, Staden U, Nocon M, Beyer K, et al. The predictive value of specific immunoglobulin E levels in serum for the outcome of oral food challenges. Clin Exp Allergy 2005;35:268-273

Summary Background Specific serum IgE is considered as one of the important diagnostic measures in the diagnostic work-up of food allergy. Objective To evaluate the role of specific serum IgE in predicting the outcome of oral food challenges, and to determine threshold concentrations of specific serum IgE that could render double-blind, placebo-controlled food challenges unnecessary. Methods In 501 children (median age 13 months), 992 controlled oral challenges were performed with cow's milk (CM), hen's egg (HE), wheat and soy. 440/501 (88%) children suffered from atopic dermatitis. For all children, specific IgE concentrations in serum were determined. Sensitivity, specificity, positive and negative predictive values, receiver operator characteristics-curves as well as predictive decision points were calculated. Results Four hundred and forty-five out of 992 oral food challenges with allergens were assessed as positive. Sensitivity of specific serum IgE was 97% for HE, 83% for CM, 69% for soy, and 79% for wheat. Specificity was 51% for HE, 53% for CM, 50% for soy, and 38% for wheat. Calculating 90%, 95% and 99% predicted probabilities using logistic regression revealed predictive decision points of 6.3, 12.6, and 59.2 kU/L for HE, respectively. Subdividing our children in those of below or above 1 year of age resulted in a markedly different predicted probability for HE. For CM, only the 90% predicted probability (88.8 kU/L) could be calculated. No decision points could be determined for CM, wheat and soy. Conclusion In general, specific serum IgE levels showed a correlation with the outcome of positive oral food challenges for CM and HE. Meaningful predictive decision points can be calculated for HE, which may help to avoid oral food challenges in some cases. However, data need to be ascertained for each allergen separately. Furthermore, the age of the patient population under investigation must also be taken into account.

↩

[119] - Komata T, Söderström L, Borres MP, Tachimoto H, Ebisawa M. The predictive relationship of food-specific serum IgE concentrations to challenge outcomes for egg and milk varies by patient age. J Allergy Clin Immunol 2007;119:1272-1274

↩

[120] - Mehl A, Rolinck-Werninghaus C, Staden U, Verstege A, Wahn U, Beyer K, et al. The atopy patch test in the diagnostic workup of suspected food-related symptoms in children. J Allergy Clin Immunol 2006;118:923-929

BACKGROUND: There is an increasing need to develop test instruments that make oral food challenges superfluous . OBJECTIVE: We sought to study the utility of atopy patch tests (APTs) in the diagnostic workup of food allergy . METHODS: We investigated 437 children (median age, 13 months; 90% with atopic dermatitis) referred for evaluation of suspected food allergy. Specific serum IgE (sIgE) measurements, skin prick tests (SPTs), APTs, and controlled oral food challenges were performed . RESULTS: We analyzed 873 oral challenges with cow's milk, hen's egg, wheat, and/or soy. One thousand seven hundred single APTs were performed. As a single parameter, the APTs showed the best specificity compared with sIgE measurements, SPTs, or both. Combining the APT with either the SPT or sIgE measurement resulted in improved sensitivity and specificity. Decision points for sIgE measurement and for the SPT showed lower values when combined with a positive APT result. Correctly bypassing an oral food challenge with combined testing, including APTs, only between 0.5% and 7% (99% predicted probability) and between 6% and 14% (using 95% predicted probability) of children would fulfill the criteria for avoiding an oral food challenge . CONCLUSION: Although the predictive capacity of the APT is improved when combined with sIgE measurement or the SPT, oral food challenges become superfluous in only 0.5% to 14% of study patients. In addition, the APT is time consuming and demands a highly experienced test evaluator. CLINICAL IMPLICATIONS: For daily clinical practice, the APT adds only a small predictive value to the standard SPT and sIgE measurement in the diagnostic workup of suspected food-related symptoms in our study population.

↩

[121] - Östblom E, Lilja G, Ahlstedt S, van Hage M, Wickman M. Patterns of quantitative food-specific IgE-antibodies and reported food hypersensitivity in 4-year-old children. Allergy 2008;63:418-424

BACKGROUND: Diagnosis of food hypersensitivity (FHS) is difficult and interpretation of food allergy tests is complicated . OBJECTIVE: To investigate the probability of reported FHS in relation to levels of food-specific IgE-antibodies (AB) in a population-based setting of 4-year-old children (n = 2336) . METHODS: Information on FHS was obtained from a questionnaire and specific IgE-AB to milk, egg, fish, peanut, soy and wheat were analysed . RESULTS: Thirty-one per cent of the children with reported FHS (n = 284) were sensitized (> or =0.35 kU(A)/l) to at least one of the tested foods compared with 11% of children without FHS (n = 2052). Furthermore, the probability of reported symptoms to milk, egg and fish increased with increasing levels of food-specific IgE-AB to the same food allergens. A similar trend was seen for peanut and wheat, but not for soy. Increasing levels of specific IgE-AB to milk or egg were also associated with an increasing risk of reported symptoms caused by other foods . CONCLUSIONS: Quantitative measurements of IgE-AB to milk, egg and fish are useful to evaluate IgE-associated FHS in preschool children also in a population based sample. Such measurements appear to be of limited value for soy bean and wheat, in particular as a screening method.

↩

[122] - Benhamou AH, Zamora SA, Eigenmann PA. Correlation between specific immunoglobulin E levels and the severity of reactions in egg allergic patients. Pediatr Allergy Immunol 2008;19:173-179

Different studies proposed specific immunoglobulin E (IgE) cut-off levels for the diagnosis of egg allergy. Little is known if IgE titres could be helpful for prediction of the severity of the reaction. The aim of this study was to determine whether IgE titres are associated with the severity of the reaction during a standardized egg challenge. We reviewed data obtained during oral challenge tests to egg performed between 2003 and 2005, and attributed a clinical score to the positive reactions. Serum specific IgE levels were analysed in relation with the severity of the reaction. We analysed data from 51 oral food challenges to egg, raw or cooked. Sixteen challenges (31%) were negative and 35 (69%) were positive of which 13 challenges (37% of positive reactions) elicited a severe reaction. IgE levels in our patients ranged from undetectable to 14.90 kU/l. We could determine a cut-off level of 8.20 kU/l for a 90% probability of clinical reactivity. IgE titres were statistically significantly different between the patients with absent, mild and moderate or severe reaction. Patients with negative challenge had IgE levels between 0.35 and 6.41 kU/l (median 1.17), those with mild and moderate reaction had IgE levels ranging from 0.35 to 14.90 (median 2.47) and patients with severe reactions had IgE between 1.18 and 11.00 (median 3.70) (p = 0.006). Our results show a correlation between IgE titres and the severity of the clinical reaction to egg. IgE titres may help to determine the potential risk of a reaction to eggs.

↩

[123] - Osterballe M, Bindslev-Jensen C. Threshold levels in food challenge and specific IgE in patients with egg allergy: Is there a relationship ? J Allergy Clin Immunol 2003;112:196-201

BACKGROUND: Previously published articles described a relationship between food-specific IgE and the outcome of food challenge in children with egg allergy. These investigations defined different levels of predictive values in different study populations and thus pointed toward the possibility of a certain level of specific IgE to egg white predicting a positive outcome in food challenge . OBJECTIVE: The purpose of this study was to determine the utility of specific IgE in estimating threshold level to predict a positive outcome in food challenge . METHODS: Fifty-six children were evaluated for egg allergy by titrated oral challenges. Sera were analyzed for specific IgE to egg white in 56 patients by using the Magic Lite test and 32 of 56 patients also by the CAP test. Values of specific IgE to egg white were compared to the outcome of challenges and the threshold level . RESULTS: The diagnostic level of specific IgE predicting clinical reactivity in this population with greater than 95% certainty was identified as 10.8 standardized units/mL (Magic Lite) and 1.5 kilounits of allergen-specific IgE/L (CAP), respectively. We found no significant relationship between the specific IgE concentration (egg white) and the challenge threshold level . CONCLUSION: Although the specific IgE concentration correlated to a positive outcome in food challenge, there was no significant relationship between the quantification of specific IgE and the challenge threshold level. Therefore the standardized food challenge still remains the gold standard in the diagnosis of food allergy.

↩

[124] - Mehl A, Verstege A, Staden U, Kulig M, Nocon M, Beyer K, et al. Utility of the ratio of food-specific IgE/total IgE in predicting symptomatic food allergy in children. Allergy 2005;60:1034-1039

BACKGROUND: Double-blind, placebo-controlled food challenges are time-consuming, expensive and not without risk to patients. Therefore, an in vitro test that could accurately diagnose food allergy would be of great value . OBJECTIVE: To evaluate the utility of the ratio of specific immunoglobulin E (IgE)/total IgE compared with specific IgE (sIgE) alone in predicting symptomatic food allergy . METHODS: We retrospectively analysed 992 controlled oral food challenges performed in 501 children (median age 13 months). The ratio of sIgE/total IgE was calculated and tested for correlation with the outcome of food challenges. Receiver operator characteristics (ROC)-curves were performed; predicted probabilities and predictive decision points were calculated . RESULTS: A significant correlation was found between the ratio and the outcome of food challenges for cow's milk (CM), hen's egg (HE), and wheat, but not for soy. The ROC and predicted probability curves as well as sensitivity and specificity of the decision points of the ratio were similar to those of sIgE levels for CM, HE and wheat . CONCLUSION: In view of the greater effort needed to determine the ratio, without benefit compared with the sIgE alone, the calculation of the ratio of sIgE/total IgE for diagnosing symptomatic food allergy offers no advantage for CM, HE, wheat or soy. For the majority of cases controlled oral food challenges still remain the method of choice.

↩

[125] - Verstege A, Mehl A, Rolinck-Werninghaus C, Staden U, Nocon M, Beyer K, et al. The predictive value of the skin prick test weal size for the outcome of oral food challenges. Clin Exp Allergy 2005;35:1220-1226

BACKGROUND: The skin prick test (SPT) is regarded as an important diagnostic measure in the diagnostic work-up of food allergy. Objective To evaluate the diagnostic capacity of the SPT in predicting the outcome of oral food challenges, and to determine decision points for the weal size and the skin index (SI) that could render double-blind, placebo-controlled food challenges unnecessary . METHODS: In 385 children (median age 22 months), 735 controlled oral challenges were performed with cow's milk (CM), hen's egg (HE), wheat and soy. Three hundred and thirty-six of 385 (87%) children suffered from atopic dermatitis. SPT was performed in all children. Diagnostic capacity, receiver-operator characteristics (ROC) curves and predictive decision points were calculated for the mean weal size and the calculated SI . RESULTS: Three hundred and twelve of 735 (43%) oral food challenges were assessed to be positive. Calculation of 95% and 99% predicted probabilities using logistic regression revealed predictive decision points of 13.0 and 17.8 mm for HE, and 12.5 and 17.3 mm for CM, respectively. However, using the SI, the corresponding cut-off levels were 2.6 and 3.7, respectively, for HE, and 2.7 and 3.7 for CM. For wheat, 95% and 99% decision points of 2.2 and 3.0 were found in children below 1 year of age . CONCLUSION: Predictive decision points for a positive outcome of food challenges can be calculated for HE and CM using weal size and SI. They may help to avoid oral food challenges.

↩

[126] - Knight AK, Shreffler WG, Sampson HA, Sicherer SH, Noone S, Mofidi S, et al. Skin prick test to egg white provides additional diagnostic utility to serum egg white-specific IgE antibody concentration in children. J Allergy Clin Immunol 2006;117:842-847

BACKGROUND: Levels of IgE antibody to egg white of greater than 7 kIU/L are highly predictive of clinical reactivity to egg, and lower levels often require evaluation with oral food challenge (OFC) to establish definitive diagnosis. OFCs have inherent risks, and diagnostic criteria indicating high likelihood of passing would be clinically useful . OBJECTIVE: We sought to determine whether the size of the skin prick test (SPT) to egg white adds diagnostic utility for children with low egg white-specific IgE antibody levels . METHODS: A retrospective analysis of clinical history, egg white-specific IgE antibody levels, SPT responses, and egg OFC outcomes was performed . RESULTS: Children who passed (n = 29) egg OFCs and those who failed (n = 45) did not differ significantly in age, clinical characteristics, or egg white-specific IgE levels. There were, however, significant differences between both egg white SPT wheal response size and egg/histamine SPT wheal index. Children who failed egg OFCs had a median wheal of 5.0 mm; those who passed had a median wheal of 3.0 mm (P = .003). Children who failed egg OFCs had a median egg/histamine index of 1.00; those who passed had a median index of 0.71 (P = .001). For egg white-specific IgE levels of less than 2.5 kIU/L, an SPT wheal of 3 mm or an egg/histamine index of 0.65 was associated with a 50% chance of passing . CONCLUSION: In children with low egg white-specific IgE levels, those with smaller SPT wheal responses to egg were more likely to pass an egg OFC than those with larger wheal responses. The size of the egg white SPT response might provide additional information to determine the timing of egg OFC. CLINICAL IMPLICATIONS: The size of the egg white SPT wheal response might provide the clinician with additional information to determine the timing of egg OFC in children with low egg white-specific IgE antibody levels.

↩

[127] - Shek LPC, Soderstrom L, Ahlstedt S, Beyer K, Sampson HA. Determination of food specific IgE levels over time can predict the development of tolerance in cow's milk and hen's egg allergy. J Allergy Clin Immunol 2004;114:387-391

Background The majority of children with cow's milk and hen's egg allergy develop clinical tolerance with time. However, there are no good indices to predict when and in whom this occurs. Objective The aim of this study was to determine if monitoring food specific IgE levels over time could be used as a predictor for determining when patients develop clinical tolerance. Methods Eighty-eight patients with hen's egg and 49 patients with cow's milk allergy who underwent repeated double-blind, placebo-controlled food challenges were included in the study. Using the Pharmacia CAP-System FEIA, specific IgE (sIgE) levels to cow's milk and hen's egg were retrospectively determined from stored serum samples obtained at the time of the food challenges. Logistic regression was used to evaluate the relationship between tolerance development and the decrease in sIgE levels over a specific time period between the two challenges. Results Twenty-eight of the 66 egg-allergic and 16 of the 33 milk-allergic patients lost their allergy over time. For egg, the decrease in sIgE levels (P=.0014) was significantly related to the probability of developing clinical tolerance, with the duration between challenges having an influence (P=.06). For milk there also was a significant relationship between the decrease in sIgE levels (P=.0175) and the probability of developing tolerance to milk but no significant contribution with regard to time. Stratification into 2 age groups, those below 4 years of age and those above 4 years of age at time of first challenge, had an effect, with the younger age group being more likely to develop clinical tolerance in relation to the rate of decrease in sIgE. The median food sIgE level at diagnosis was significantly less for the group developing „tolerance‰ to egg (P < .001), and a similar trend was seen for milk allergy (P=.06). Using these results, we developed a model for predicting the likelihood of developing tolerance in milk and egg allergy based on the decrease in food sIgE over time. Conclusion We found that the rate of decrease in food sIgE levels over time was predictive for the likelihood of developing tolerance in milk and egg allergy. Using the likelihood estimates from this study could aid clinicians in providing prognostic information and in timing subsequent food challenges, thereby decreasing the number of premature and unnecessary double-blind, placebo-controlled food challenges

↩

[128] - Wickman M, Lilja G, Söderström L, van Hage-Hamsten M, Ahlstedt S. Quantitative analysis of IgE antibodies to food and inhalant allergens in 4-year-old children reflects their likelihood of allergic disease. Allergy 2005;60:650-657

BACKGROUND: It is well established that early diagnosis of allergic disease is warranted . METHODS: In a prospective birth cohort study (BAMSE) 3743 children at 4 years of age were included. Children were classified as having any allergic disease, e.g. asthma, suspected allergic rhinitis (suspAR), eczema or oro-gastro-intestinal symptoms with questionnaire. Blood was obtained from 2612 of these children and analysed for IgE antibodies (ab) towards 14 common food and airborne allergens . RESULTS: Positive IgE ab results were found in 38% of the children with any allergic disease, whereas such IgE ab results were found in 17% among those without any allergic disease. Furthermore, among children with any allergic disease the median summated IgE ab levels were 10.7 kU(A)/l compared with 1.5 kU(A)/l among those without such symptoms. The highest IgE ab levels were found to birch, peanut, cat and horse. When the sum of the IgE-ab levels towards the selected allergens was at least 34 kU(A)/l, or, alternatively, more than four allergen tests were positive, there was a 75% likelihood of identifying the individual with any allergic disease. To identify those with asthma, as well as those with suspAR, a significant interaction was found for the combination of the sum of IgE-ab levels and number of allergens positive at test. For eczema only, the number of positive allergens at test was associated to the likelihood of such disease . CONCLUSIONS: In children, 4 years of age, allergic disease was frequently not associated with the presence of single positive IgE antibody results, whereas increased IgE ab levels were significantly more prevalent among those with allergic disease. Thus, testing a certain profile of airborne and food allergens, and utilizing the sum of the IgE-ab levels in combination with the number of allergens positive at tests, may represent a more efficient diagnostic tool then to use just single positive IgE-ab results.

↩

[129] - Sampson HA, Ho DG. Relationship between food-specific IgE concentrations and the risk of positive food challenges in children and adolescents. J Allergy Clin Immunol 1997;100:444-451

"BACKGROUND: The double-blind, placebo-controlled food challenge (DBPCFC) is the ""gold standard"" for diagnosis of food hypersensitivity. Skin prick tests and RASTs are sensitive indicators of food-specific IgE antibodies but poor predictors of clinical reactivity. Previous studies suggested that high concentrations of food-specific IgE antibody were predictive of food-induced clinical symptoms. Because the CAP System FEIA (Pharmacia Diagnostics, Uppsala, Sweden) provides a quantitative assessment of allergen-specific IgE antibody, this study was undertaken to determine the potential utility of the CAP System FEIA in diagnosis of IgE-mediated food hypersensitivity . METHODS: Sera from 196 patients with food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by CAP System FEIA. Sera were randomly selected from 300 stored samples of children and adolescents who had been evaluated by history, skin prick tests, and DBPCFCs. The study population was highly atopic; all patients had atopic dermatitis, and approximately 50% had asthma and allergic rhinitis at the time of initial evaluation. The performance characteristics of the CAP System FEIA were compared with those of skin prick tests and the outcome of DBPCFCs or ""convincing"" histories of anaphylactic reactions . RESULTS: The prevalence of specific food allergies in the study population varied from 22% for wheat to 73% for egg. Allergy to egg, milk, peanut, and soy accounted for 87% of confirmed reactions. The performance characteristics of skin prick tests and CAP System FEIA (egg, milk, peanut, fish) were comparable, with excellent sensitivity and negative predictive accuracy but poor specificity and positive predictive accuracy. The performance characteristics of the CAP System FEIA for soy and wheat were poor. For egg, milk, peanut, and fish allergy, diagnostic levels of IgE, which could predict clinical reactivity in this population with greater than 95% certainty, were identified: egg, 6 kilounits of allergen-specific IgE per liter (kU[A]/L); milk, 32 kU(A)/L; peanut, 15 kU(A)/L; and fish, 20 kU(A)/L . CONCLUSIONS: When compared with the outcome of DBPCFCs, results of CAP System FEIA are generally comparable to those of skin prick tests in predicting symptomatic food hypersensitivity. Furthermore, by measuring the concentrations of food-specific IgE antibodies with the CAP System FEIA, it is possible to identify a subset of patients who are highly likely (>95%) to experience clinical reactions to egg, milk, peanut, or fish. This could eliminate the need to perform DBPCFCs in a significant number of patients suspected of having IgE-mediated food allergy."

↩

[130] - Sampson HA. Utility of food-specific IgE concentrations in predicting symptomatic food allergy. J Allergy Clin Immunol 2001;107:891-896

BACKGROUND: The double-blind, placebo-controlled food challenge is considered the gold standard for diagnosing food allergy. However, in a retrospective analysis of children and adolescents with atopic dermatitis and food allergy, discrete food-specific IgE concentrations were established that could predict clinical reactivity to egg, milk, peanut, and fish with greater than 95% certainty. OBJECTIVE: The purpose of this investigation was to determine the utility of these 95% predictive decision points in a prospective evaluation of food allergy. METHODS: Sera from 100 consecutive children and adolescents referred for evaluation of food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by using the Pharmacia CAP System FEIA. Food-specific IgE values were compared with history and the results of skin prick tests and food challenges to determine the efficacy of previously established 95% predictive decision points in identifying patients with increased probability of reacting during a specific food challenge. RESULTS: One hundred children (62% male; median age, 3.8 years; range, 0.4-14.3 years) were evaluated for food allergy. The diagnosis of food allergy was established by means of history or oral food challenge. On the basis of the previously established 95% predictive decision points for egg, milk, peanut, and fish allergy, greater than 95% of food allergies diagnosed in this prospective study were correctly identified by quantifying serum food-specific IgE concentrations. CONCLUSION: In a prospective study of children and adolescents referred for evaluation of food allergy, previously established 95% predictive decision points of food-specific IgE antibody concentrations for 4 major food allergens were effective in predicting clinical reactivity. Quantification of food-specific IgE is a useful test for diagnosing symptomatic allergy to egg, milk, peanut, and fish in the pediatric population and could eliminate the need to perform double-blind, placebo-controlled food challenges in a significant number of children.

↩

[131] - Östblom E, Lilja G, Ahlstedt S, van Hage M, Wickman M. Patterns of quantitative food-specific IgE-antibodies and reported food hypersensitivity in 4-year-old children. Allergy 2008;63:418-424

BACKGROUND: Diagnosis of food hypersensitivity (FHS) is difficult and interpretation of food allergy tests is complicated . OBJECTIVE: To investigate the probability of reported FHS in relation to levels of food-specific IgE-antibodies (AB) in a population-based setting of 4-year-old children (n = 2336) . METHODS: Information on FHS was obtained from a questionnaire and specific IgE-AB to milk, egg, fish, peanut, soy and wheat were analysed . RESULTS: Thirty-one per cent of the children with reported FHS (n = 284) were sensitized (> or =0.35 kU(A)/l) to at least one of the tested foods compared with 11% of children without FHS (n = 2052). Furthermore, the probability of reported symptoms to milk, egg and fish increased with increasing levels of food-specific IgE-AB to the same food allergens. A similar trend was seen for peanut and wheat, but not for soy. Increasing levels of specific IgE-AB to milk or egg were also associated with an increasing risk of reported symptoms caused by other foods . CONCLUSIONS: Quantitative measurements of IgE-AB to milk, egg and fish are useful to evaluate IgE-associated FHS in preschool children also in a population based sample. Such measurements appear to be of limited value for soy bean and wheat, in particular as a screening method.

↩

[132] - Malandain H. The clinical use of specific IgE antibody testing – a further word of caution. Allergy 2004;59:359-360

↩

[133] - Simpson A, Söderström L, Ahlstedt S, Murray CS, Woodcock A, Custovic A. IgE antibody quantification and the probability of wheeze in preschool children. J Allergy Clin Immunol 2005;116:744-749

BACKGROUND: IgE-mediated sensitization is usually considered a dichotomous variable (either sensitized or not). Quantitative IgE antibody analysis may better predict the expression of wheeze . OBJECTIVE: Within the context of a population-based birth cohort, we investigated the association among wheeze, lung function, and specific IgE antibody levels . METHODS: Children (n = 521) were followed to age 5 years with repeated questionnaires, skin testing, and measurement of lung function (specific airway resistance) and specific serum IgE (ImmunoCAP) . RESULTS: Using specific IgE as a continuous variable, the risk of current wheeze increased significantly with increasing IgE to mite, cat, and dog (P < .0001). When IgE levels to these 3 allergens were summed, the probability of current wheeze increased 1.33-fold (95% CI, 1.21-1.47; P < .0001) per logarithmic unit increase, corresponding to an odds ratio of 3.1 at 10 and 4.25 at 30 kU(A)/L (kilo units of Allergen per liter). Similarly, increasing sum of mite-specific, cat-specific, and dog-specific IgE was associated with reduced lung function (P = .004). Among sensitized children (n = 184), the sum of mite, cat, and dog IgE was the strongest associate of current wheeze (odds ratio, 1.28; 95% CI, 1.13-1.46; P < .001), corresponding to an odds ratio of 2.56 at 10 and 3.32 at 30 kU(A)/L. There was no association between current wheeze and the size of skin test wheal. Furthermore, the sum of IgE to mite, cat, and dog at age 3 years increased the risk of persistent wheeze by age 5 years (2.15-fold/logarithmic unit increase in the specific IgE) . CONCLUSION: IgE-mediated sensitization is not an all or nothing phenomenon. The probability of wheeze and reduced lung function increases with increasing specific IgE antibody levels.

↩

[134] - Sampson HA. Utility of food-specific IgE concentrations in predicting symptomatic food allergy. J Allergy Clin Immunol 2001;107:891-896

BACKGROUND: The double-blind, placebo-controlled food challenge is considered the gold standard for diagnosing food allergy. However, in a retrospective analysis of children and adolescents with atopic dermatitis and food allergy, discrete food-specific IgE concentrations were established that could predict clinical reactivity to egg, milk, peanut, and fish with greater than 95% certainty. OBJECTIVE: The purpose of this investigation was to determine the utility of these 95% predictive decision points in a prospective evaluation of food allergy. METHODS: Sera from 100 consecutive children and adolescents referred for evaluation of food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by using the Pharmacia CAP System FEIA. Food-specific IgE values were compared with history and the results of skin prick tests and food challenges to determine the efficacy of previously established 95% predictive decision points in identifying patients with increased probability of reacting during a specific food challenge. RESULTS: One hundred children (62% male; median age, 3.8 years; range, 0.4-14.3 years) were evaluated for food allergy. The diagnosis of food allergy was established by means of history or oral food challenge. On the basis of the previously established 95% predictive decision points for egg, milk, peanut, and fish allergy, greater than 95% of food allergies diagnosed in this prospective study were correctly identified by quantifying serum food-specific IgE concentrations. CONCLUSION: In a prospective study of children and adolescents referred for evaluation of food allergy, previously established 95% predictive decision points of food-specific IgE antibody concentrations for 4 major food allergens were effective in predicting clinical reactivity. Quantification of food-specific IgE is a useful test for diagnosing symptomatic allergy to egg, milk, peanut, and fish in the pediatric population and could eliminate the need to perform double-blind, placebo-controlled food challenges in a significant number of children.

↩

[135] - Osterballe M, Bindslev-Jensen C. Threshold levels in food challenge and specific IgE in patients with egg allergy: Is there a relationship ? J Allergy Clin Immunol 2003;112:196-201

BACKGROUND: Previously published articles described a relationship between food-specific IgE and the outcome of food challenge in children with egg allergy. These investigations defined different levels of predictive values in different study populations and thus pointed toward the possibility of a certain level of specific IgE to egg white predicting a positive outcome in food challenge . OBJECTIVE: The purpose of this study was to determine the utility of specific IgE in estimating threshold level to predict a positive outcome in food challenge . METHODS: Fifty-six children were evaluated for egg allergy by titrated oral challenges. Sera were analyzed for specific IgE to egg white in 56 patients by using the Magic Lite test and 32 of 56 patients also by the CAP test. Values of specific IgE to egg white were compared to the outcome of challenges and the threshold level . RESULTS: The diagnostic level of specific IgE predicting clinical reactivity in this population with greater than 95% certainty was identified as 10.8 standardized units/mL (Magic Lite) and 1.5 kilounits of allergen-specific IgE/L (CAP), respectively. We found no significant relationship between the specific IgE concentration (egg white) and the challenge threshold level . CONCLUSION: Although the specific IgE concentration correlated to a positive outcome in food challenge, there was no significant relationship between the quantification of specific IgE and the challenge threshold level. Therefore the standardized food challenge still remains the gold standard in the diagnosis of food allergy.

↩

[136] - Celik-Bilgili S, Mehl A, Verstege A, Staden U, Nocon M, Beyer K, et al. The predictive value of specific immunoglobulin E levels in serum for the outcome of oral food challenges. Clin Exp Allergy 2005;35:268-273

Summary Background Specific serum IgE is considered as one of the important diagnostic measures in the diagnostic work-up of food allergy. Objective To evaluate the role of specific serum IgE in predicting the outcome of oral food challenges, and to determine threshold concentrations of specific serum IgE that could render double-blind, placebo-controlled food challenges unnecessary. Methods In 501 children (median age 13 months), 992 controlled oral challenges were performed with cow's milk (CM), hen's egg (HE), wheat and soy. 440/501 (88%) children suffered from atopic dermatitis. For all children, specific IgE concentrations in serum were determined. Sensitivity, specificity, positive and negative predictive values, receiver operator characteristics-curves as well as predictive decision points were calculated. Results Four hundred and forty-five out of 992 oral food challenges with allergens were assessed as positive. Sensitivity of specific serum IgE was 97% for HE, 83% for CM, 69% for soy, and 79% for wheat. Specificity was 51% for HE, 53% for CM, 50% for soy, and 38% for wheat. Calculating 90%, 95% and 99% predicted probabilities using logistic regression revealed predictive decision points of 6.3, 12.6, and 59.2 kU/L for HE, respectively. Subdividing our children in those of below or above 1 year of age resulted in a markedly different predicted probability for HE. For CM, only the 90% predicted probability (88.8 kU/L) could be calculated. No decision points could be determined for CM, wheat and soy. Conclusion In general, specific serum IgE levels showed a correlation with the outcome of positive oral food challenges for CM and HE. Meaningful predictive decision points can be calculated for HE, which may help to avoid oral food challenges in some cases. However, data need to be ascertained for each allergen separately. Furthermore, the age of the patient population under investigation must also be taken into account.

↩

[137] - Mehl A, Rolinck-Werninghaus C, Staden U, Verstege A, Wahn U, Beyer K, et al. The atopy patch test in the diagnostic workup of suspected food-related symptoms in children. J Allergy Clin Immunol 2006;118:923-929

BACKGROUND: There is an increasing need to develop test instruments that make oral food challenges superfluous . OBJECTIVE: We sought to study the utility of atopy patch tests (APTs) in the diagnostic workup of food allergy . METHODS: We investigated 437 children (median age, 13 months; 90% with atopic dermatitis) referred for evaluation of suspected food allergy. Specific serum IgE (sIgE) measurements, skin prick tests (SPTs), APTs, and controlled oral food challenges were performed . RESULTS: We analyzed 873 oral challenges with cow's milk, hen's egg, wheat, and/or soy. One thousand seven hundred single APTs were performed. As a single parameter, the APTs showed the best specificity compared with sIgE measurements, SPTs, or both. Combining the APT with either the SPT or sIgE measurement resulted in improved sensitivity and specificity. Decision points for sIgE measurement and for the SPT showed lower values when combined with a positive APT result. Correctly bypassing an oral food challenge with combined testing, including APTs, only between 0.5% and 7% (99% predicted probability) and between 6% and 14% (using 95% predicted probability) of children would fulfill the criteria for avoiding an oral food challenge . CONCLUSION: Although the predictive capacity of the APT is improved when combined with sIgE measurement or the SPT, oral food challenges become superfluous in only 0.5% to 14% of study patients. In addition, the APT is time consuming and demands a highly experienced test evaluator. CLINICAL IMPLICATIONS: For daily clinical practice, the APT adds only a small predictive value to the standard SPT and sIgE measurement in the diagnostic workup of suspected food-related symptoms in our study population.

↩

[138] - Östblom E, Lilja G, Ahlstedt S, van Hage M, Wickman M. Patterns of quantitative food-specific IgE-antibodies and reported food hypersensitivity in 4-year-old children. Allergy 2008;63:418-424

BACKGROUND: Diagnosis of food hypersensitivity (FHS) is difficult and interpretation of food allergy tests is complicated . OBJECTIVE: To investigate the probability of reported FHS in relation to levels of food-specific IgE-antibodies (AB) in a population-based setting of 4-year-old children (n = 2336) . METHODS: Information on FHS was obtained from a questionnaire and specific IgE-AB to milk, egg, fish, peanut, soy and wheat were analysed . RESULTS: Thirty-one per cent of the children with reported FHS (n = 284) were sensitized (> or =0.35 kU(A)/l) to at least one of the tested foods compared with 11% of children without FHS (n = 2052). Furthermore, the probability of reported symptoms to milk, egg and fish increased with increasing levels of food-specific IgE-AB to the same food allergens. A similar trend was seen for peanut and wheat, but not for soy. Increasing levels of specific IgE-AB to milk or egg were also associated with an increasing risk of reported symptoms caused by other foods . CONCLUSIONS: Quantitative measurements of IgE-AB to milk, egg and fish are useful to evaluate IgE-associated FHS in preschool children also in a population based sample. Such measurements appear to be of limited value for soy bean and wheat, in particular as a screening method.

↩

[139] - Benhamou AH, Zamora SA, Eigenmann PA. Correlation between specific immunoglobulin E levels and the severity of reactions in egg allergic patients. Pediatr Allergy Immunol 2008;19:173-179

Different studies proposed specific immunoglobulin E (IgE) cut-off levels for the diagnosis of egg allergy. Little is known if IgE titres could be helpful for prediction of the severity of the reaction. The aim of this study was to determine whether IgE titres are associated with the severity of the reaction during a standardized egg challenge. We reviewed data obtained during oral challenge tests to egg performed between 2003 and 2005, and attributed a clinical score to the positive reactions. Serum specific IgE levels were analysed in relation with the severity of the reaction. We analysed data from 51 oral food challenges to egg, raw or cooked. Sixteen challenges (31%) were negative and 35 (69%) were positive of which 13 challenges (37% of positive reactions) elicited a severe reaction. IgE levels in our patients ranged from undetectable to 14.90 kU/l. We could determine a cut-off level of 8.20 kU/l for a 90% probability of clinical reactivity. IgE titres were statistically significantly different between the patients with absent, mild and moderate or severe reaction. Patients with negative challenge had IgE levels between 0.35 and 6.41 kU/l (median 1.17), those with mild and moderate reaction had IgE levels ranging from 0.35 to 14.90 (median 2.47) and patients with severe reactions had IgE between 1.18 and 11.00 (median 3.70) (p = 0.006). Our results show a correlation between IgE titres and the severity of the clinical reaction to egg. IgE titres may help to determine the potential risk of a reaction to eggs.

↩

[140] - Ott H, Baron JM, Heise R, Ocklenburg C, Stanzel S, Merk HF, et al. Clinical usefulness of microarray-based IgE detection in children with suspected food allergy. Allergy 2008;63:1521-1528

BACKGROUND: Component-resolved diagnostics using microarray technology has recently been introduced into clinical allergology, but its applicability in children with food allergy has hardly been investigated so far. The aim of this study was to evaluate the utility of microarray-based IgE detection in the diagnostic workup of food allergy and to compare this new diagnostic tool with established methods of allergen-specific IgE detection . METHODS: We investigated 130 infants and children with suspected allergy to cow's milk (CM) or hen's egg (HE). Serum IgE measurements, skin prick tests, allergen microarray assays and controlled oral food challenges with HE and CM were performed . RESULTS: We analyzed 145 oral challenges that served as reference parameters for assay performance assessment. On this basis, the panel of microarrayed allergen components was shown to represent a comprehensive repertoire of clinically relevant CM and HE proteins. Additionally, the implemented CM and HE components respectively sufficed for equivalent test performance as compared to the corresponding fluorescence enzyme immunoassay extract and skin testing. However, component-resolved diagnostics for HE and CM allergy did not make oral food challenges superfluous. Clinical IgE decision points predicting positive oral food challenges could be calculated for both in vitro test methods . CONCLUSIONS: Allergen microarrays provide a new tool to diagnose symptomatic CM and HE allergy. They show performance characteristics comparable to the current diagnostic tests and may be indicated in small children in whom only small blood volumes are obtainable. However, they are not capable of replacing double-blind, placebo-controlled food challenges in most cases.

↩

[141] - Benhamou AH, Zamora SA, Eigenmann PA. Correlation between specific immunoglobulin E levels and the severity of reactions in egg allergic patients. Pediatr Allergy Immunol 2008;19:173-179

Different studies proposed specific immunoglobulin E (IgE) cut-off levels for the diagnosis of egg allergy. Little is known if IgE titres could be helpful for prediction of the severity of the reaction. The aim of this study was to determine whether IgE titres are associated with the severity of the reaction during a standardized egg challenge. We reviewed data obtained during oral challenge tests to egg performed between 2003 and 2005, and attributed a clinical score to the positive reactions. Serum specific IgE levels were analysed in relation with the severity of the reaction. We analysed data from 51 oral food challenges to egg, raw or cooked. Sixteen challenges (31%) were negative and 35 (69%) were positive of which 13 challenges (37% of positive reactions) elicited a severe reaction. IgE levels in our patients ranged from undetectable to 14.90 kU/l. We could determine a cut-off level of 8.20 kU/l for a 90% probability of clinical reactivity. IgE titres were statistically significantly different between the patients with absent, mild and moderate or severe reaction. Patients with negative challenge had IgE levels between 0.35 and 6.41 kU/l (median 1.17), those with mild and moderate reaction had IgE levels ranging from 0.35 to 14.90 (median 2.47) and patients with severe reactions had IgE between 1.18 and 11.00 (median 3.70) (p = 0.006). Our results show a correlation between IgE titres and the severity of the clinical reaction to egg. IgE titres may help to determine the potential risk of a reaction to eggs.

↩

[142] - Osterballe M, Bindslev-Jensen C. Threshold levels in food challenge and specific IgE in patients with egg allergy: Is there a relationship ? J Allergy Clin Immunol 2003;112:196-201

BACKGROUND: Previously published articles described a relationship between food-specific IgE and the outcome of food challenge in children with egg allergy. These investigations defined different levels of predictive values in different study populations and thus pointed toward the possibility of a certain level of specific IgE to egg white predicting a positive outcome in food challenge . OBJECTIVE: The purpose of this study was to determine the utility of specific IgE in estimating threshold level to predict a positive outcome in food challenge . METHODS: Fifty-six children were evaluated for egg allergy by titrated oral challenges. Sera were analyzed for specific IgE to egg white in 56 patients by using the Magic Lite test and 32 of 56 patients also by the CAP test. Values of specific IgE to egg white were compared to the outcome of challenges and the threshold level . RESULTS: The diagnostic level of specific IgE predicting clinical reactivity in this population with greater than 95% certainty was identified as 10.8 standardized units/mL (Magic Lite) and 1.5 kilounits of allergen-specific IgE/L (CAP), respectively. We found no significant relationship between the specific IgE concentration (egg white) and the challenge threshold level . CONCLUSION: Although the specific IgE concentration correlated to a positive outcome in food challenge, there was no significant relationship between the quantification of specific IgE and the challenge threshold level. Therefore the standardized food challenge still remains the gold standard in the diagnosis of food allergy.

↩

[143] - Sicherer SH, Morrow EH, Sampson HA. Dose-response in double-blind, placebo-controlled oral food challenges in children with atopic dermatitis. J Allergy Clin Immunol 2000;105:582-586

"BACKGROUND: Double-blind, placebo-controlled oral food challenges (DBPCFCs) are considered the ""gold standard"" for diagnosing food hypersensitivity, but the dose that elicits positive challenges, or determinants that may predict dose-response relationships, have not been reported . OBJECTIVE: Our purpose was to determine the quantity of food that elicits reactions during DBPCFCs and to evaluate parameters that may predict the provocative dose and severity of reaction . METHODS: We reviewed challenge data for all positive challenges to 6 common allergenic foods in children with atopic dermatitis evaluated for food allergy over a 13-year period. Challenge food was generally administered in 6 doses at 10- to 15-minute intervals beginning with 400 to 500 mg and completing with a total of 8 to 10 g of food. An open feeding of a larger portion followed negative challenges. At the physician's discretion, a lower starting dose was occasionally used (100 mg, 250 mg). Food-specific IgE antibody concentrations (radioallergosorbent test [RAST]) were determined on stored sera of 20% of the challenges selected randomly and 99.6% had prick skin tests (PSTs) performed to the challenged food . RESULTS: A total of 196 children (45% male; median age 5 y 9 mo; atopic dermatitis 98%, asthma 62%) had 513 positive challenges distributed as follows: egg 267, milk 117, soy 53, wheat 40, peanut 24, fish 12. The percentage of children reacting at the first dose (500 mg or less) was as follows: egg 49%, milk 55%, soy 28%, wheat 25%, peanut 26%, and fish 17%. Twenty-six milk challenges and 22 egg challenges were positive at a first dose of 250 mg; 3 milk challenges and 7 egg challenges were positive at a first dose of 100 mg. Eleven percent of the reactions that occurred on the first dose were severe. The percentage reacting after the final dose of the DBPCFC (or during open challenge) were egg 11%, milk 12%, soy 19%, wheat 12.5%, peanut 8.7%, and fish 25%. There was not a strong correlation between PST absolute wheal size or score (adjusted for histamine controls) and dose at reaction or severity of reaction (R(s) range -0.22 to 0.39 for particular foods). Serum concentration of food-specific IgE did not correlate well with the dose causing a reaction or with severity (R(s) range -0.40 to 0.55 for particular foods) . CONCLUSIONS: This food-allergic population may react to as little as 100 mg of food, possibly less, and the dose causing a reaction and the severity of reaction is not predicted by PST or RAST. Lower doses (100 mg or less) should be investigated for their appropriateness in initiating DBPCFCs."

↩

[144] - Benhamou AH, Zamora SA, Eigenmann PA. Correlation between specific immunoglobulin E levels and the severity of reactions in egg allergic patients. Pediatr Allergy Immunol 2008;19:173-179

Different studies proposed specific immunoglobulin E (IgE) cut-off levels for the diagnosis of egg allergy. Little is known if IgE titres could be helpful for prediction of the severity of the reaction. The aim of this study was to determine whether IgE titres are associated with the severity of the reaction during a standardized egg challenge. We reviewed data obtained during oral challenge tests to egg performed between 2003 and 2005, and attributed a clinical score to the positive reactions. Serum specific IgE levels were analysed in relation with the severity of the reaction. We analysed data from 51 oral food challenges to egg, raw or cooked. Sixteen challenges (31%) were negative and 35 (69%) were positive of which 13 challenges (37% of positive reactions) elicited a severe reaction. IgE levels in our patients ranged from undetectable to 14.90 kU/l. We could determine a cut-off level of 8.20 kU/l for a 90% probability of clinical reactivity. IgE titres were statistically significantly different between the patients with absent, mild and moderate or severe reaction. Patients with negative challenge had IgE levels between 0.35 and 6.41 kU/l (median 1.17), those with mild and moderate reaction had IgE levels ranging from 0.35 to 14.90 (median 2.47) and patients with severe reactions had IgE between 1.18 and 11.00 (median 3.70) (p = 0.006). Our results show a correlation between IgE titres and the severity of the clinical reaction to egg. IgE titres may help to determine the potential risk of a reaction to eggs.

↩

[145] - Wells RD, Chinen J, Davis CM. Correlation of Initial Clinical Presentation and Egg White Specific IgE Values in a Cohort of 104 Egg Allergic Patients. J Allergy Clin Immunol 2008;121:S253

RATIONALE: Because the probability of a negative food challenge with egg correlates with the level of egg white specific IgE antibody (egg white- IgE), we investigated the correlation between initial egg white-IgE and initial clinical severity of egg hypersensitivity. METHODS: A retrospective chart review of the initial clinical symptoms (defined as the initial clinic visit), initial egg white-IgE, and initial total serum IgE values of 104 egg allergic patients (median age: 13.5 months, range: 9 months to 20 years of age), at a tertiary clinic was analyzed. We used a classification similar to one previously reported for tree nut allergy (Fleisher et al. 2005), which stratified patients into mild, moderate, and severe reactions. RESULTS: Fifty seven percent of the patients demonstrated mild reactions (mucosal and/or cutaneous manifestations), 34% presented with moderate reactions (respiratory, angioedema, and/or gastrointestinal symptoms), and 9 patients (9%) had severe reactions (anaphylaxis like symptoms) at initial clinical presentation. All patients with severe reactions were _ 24 months of age (6/9 were < 12 months of age). The initial egg white-IgE was lowest in the severe group (median/range: 3.2/0.44-44 KU/L; mild: 8.39/0.35-100 KU/L; moderate: 9.64/0.66-100 KU/L). The initial serum total IgE was highest in the severe group (median/range: 519/7-1,987 IU/mL; mild: 437/7-13,100 IU/ml; moderate: 299/23-52,400 IU/mL). Higher serum total IgE values were associated with urticaria (p < 0.03) and eczema (p < 0.01). CONCLUSIONS: Severe initial presentation of egg hypersensitivity does not seem to be associated with higher egg white specific IgE levels. In our cohort the severe reactions occurred in the youngest patients.

↩

[146] - Sicherer SH, Morrow EH, Sampson HA. Dose-response in double-blind, placebo-controlled oral food challenges in children with atopic dermatitis. J Allergy Clin Immunol 2000;105:582-586

"BACKGROUND: Double-blind, placebo-controlled oral food challenges (DBPCFCs) are considered the ""gold standard"" for diagnosing food hypersensitivity, but the dose that elicits positive challenges, or determinants that may predict dose-response relationships, have not been reported . OBJECTIVE: Our purpose was to determine the quantity of food that elicits reactions during DBPCFCs and to evaluate parameters that may predict the provocative dose and severity of reaction . METHODS: We reviewed challenge data for all positive challenges to 6 common allergenic foods in children with atopic dermatitis evaluated for food allergy over a 13-year period. Challenge food was generally administered in 6 doses at 10- to 15-minute intervals beginning with 400 to 500 mg and completing with a total of 8 to 10 g of food. An open feeding of a larger portion followed negative challenges. At the physician's discretion, a lower starting dose was occasionally used (100 mg, 250 mg). Food-specific IgE antibody concentrations (radioallergosorbent test [RAST]) were determined on stored sera of 20% of the challenges selected randomly and 99.6% had prick skin tests (PSTs) performed to the challenged food . RESULTS: A total of 196 children (45% male; median age 5 y 9 mo; atopic dermatitis 98%, asthma 62%) had 513 positive challenges distributed as follows: egg 267, milk 117, soy 53, wheat 40, peanut 24, fish 12. The percentage of children reacting at the first dose (500 mg or less) was as follows: egg 49%, milk 55%, soy 28%, wheat 25%, peanut 26%, and fish 17%. Twenty-six milk challenges and 22 egg challenges were positive at a first dose of 250 mg; 3 milk challenges and 7 egg challenges were positive at a first dose of 100 mg. Eleven percent of the reactions that occurred on the first dose were severe. The percentage reacting after the final dose of the DBPCFC (or during open challenge) were egg 11%, milk 12%, soy 19%, wheat 12.5%, peanut 8.7%, and fish 25%. There was not a strong correlation between PST absolute wheal size or score (adjusted for histamine controls) and dose at reaction or severity of reaction (R(s) range -0.22 to 0.39 for particular foods). Serum concentration of food-specific IgE did not correlate well with the dose causing a reaction or with severity (R(s) range -0.40 to 0.55 for particular foods) . CONCLUSIONS: This food-allergic population may react to as little as 100 mg of food, possibly less, and the dose causing a reaction and the severity of reaction is not predicted by PST or RAST. Lower doses (100 mg or less) should be investigated for their appropriateness in initiating DBPCFCs."

↩

[147] - Monti G, Muratore MC, Peltran A, Bonfante G, Silvestro L, Oggero R, et al. High incidence of adverse reactions to egg challenge on first known exposure in young atopic dermatitis children: predictive value of skin prick test and radioallergosorbent test to egg proteins. Clin Exp Allergy 2002;32:1515-1519

↩

[148] - Moneret-Vautrin DA, Morisset M, Lemerdy P, Hatahet R, Frentz P, Cuny JM. Are low levels of specific IgE useful in diagnosing clinically relevant food sensitization ? Eur Ann Allergy Clin Immunol 2006;38:307-309

↩

[149] - Desai S, Kerns L, Seshadri R, Pongracic JA. Outcomes of Oral Food Challenge with Undetectable Allergen- Specific IgE. AAAAI 62nd Annual Meeting, Miami, 3-7 March 2006, Poster n°197

RATIONALE: Food-specific IgE is utilized to predict oral tolerance Despite undetectable food-specific IgE, some children exhibit reactions during oral food challenge (OFC). The goals of this study were to evaluate features of these reactions to determine whether non-IgE-mediated responses occurred and to identify potential risk factors for positive OFC METHODS: Retrospective chart review of 202 OFCs was performed Undetectable food-specific IgE was present in 72 OFCs in 60 children (age <18yrs). Data were analyzed using generalized estimating equations for binary data to account for the clustering of outcomes by patient RESULTS: Reactions occurred in 12.5% of OFCs in which food-specific IgE was undetectable. Symptoms were seen in 14% of egg (n=21), 6% of cow milk (n=16), 25% of peanut (n=12), 33% of soy (n=3) and 0% of shellfish (n=3) challenges. Oral (22%), upper respiratory (22%), cutaneous (11%) and gastrointestinal (11%) manifestations were observed. No lower respiratory or cardiovascular symptoms occurred. Treatment was administered in 89% of OFCs; epinephrine was required in 22%. No significant differences were observed between patients that passed or failed OFC for skin test positivity, atopic disease, other food allergies, prior food challenges, timing between initial reaction and challenge, and manifestations during challenge CONCLUSIONS: Despite undetectable food-specific IgE, 12.5% of OFCs were positive. Reactions were consistent with IgE-mediated responses. No risk factor predicted which patients with undetectable foodspecific IgE may react during OFC Funding: Northwestern University - Children's Memorial Hospital

↩

[150] - Johnson J, Cronin J, Morales MB, Hogan AD. Reliability of Food-Specific Serum IgE Values in Determining Negative Outcomes in Oral Food Challenges. J Allergy Clin Immunol 2008;121:S247

RATIONALE: The purpose of this study was to determine whether low Immuno capRAST values can predict negative food challenges. METHODS: A retrospective chart review was conducted for all patients who underwent oral food challenges (OFC) between January 2003 and April 2007. Statistical analyses included descriptive statistics and frequencies and Mann-Whitney U test using SPSS 15.0. RESULTS: 202 patients underwent 268 challenges to multiple foods; 60% were male, 68% Caucasian, and the median age was 3.6 years. Patients demonstrated atopy, including atopic dermatitis (70%), allergic rhinitis (83%), and asthma (49%). 32% (n = 86) demonstrated significant allergic symptoms, resulting in a positive food challenge. Positive challenges for patients with negative CAP-RAST values, (_<.35 kilo units of allergen per liter (kUA/L)), were 32% (n=6/19) for milk, 23% (n=5/22) for egg, and 17% (n=5/29) for peanut. For values between 0.35 and 2 kUA/L, positive challenges occurred in 30% for milk (n = 8/27), 43% for egg (n = 12/28) and 47% for peanut (n = 15/32). For CAP-RAST values between 0.35 kUA/L and 5 kUA/L, there were no statistically significant differences in median IgE values for positive and negative challenges for peanut (p=0.3) or egg (p = 0.9). A statistical difference was observed for milk (p < 0.02). In failed challenges for egg, milk, and peanut, urticaria occurred in 86%, respiratory symptoms 15%, gastrointestinal symptoms 17% and cardiovascular symptoms in 1%. CONCLUSIONS: CAP-RAST levels < 0.35 kUA/L for egg, milk, and peanut do not correlate well with food challenge outcomes. Allergenspecific IgE values at low concentrations are not useful predictors of challenge outcomes.

↩

[151] - Lemon-Mule H, Sampson HA, Sicherer SH, Shreffler WG, Noone S, Nowak-Wegrzyn A. Immunologic changes in children with egg allergy ingesting extensively heated egg. J Allergy Clin Immunol 2008;122:977-983

BACKGROUND: Prior studies have suggested that heated egg might be tolerated by some children with egg allergy . OBJECTIVE: We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated . METHODS: Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg-tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg . RESULTS: Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg-reactive subjects had larger skin test wheals and greater egg white-specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg- and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels . CONCLUSIONS: The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

↩

[152] - Fiocchi A, Sarratud T, Martelli A, Terracciano L, Signoroni P. Allergy to egg white and allergy to egg yolk. EAACI 25th Congress, Vienna, 10-14 June, 2006, Poster n°576

Background Challenge with egg proteins is performed using whole egg extracts. However, allergising proteins of both white and yolk differ. Objective We sought to evaluate the response to white and yolk at challenge in a population of children presenting with symptoms attributed to egg. Methods 91 challenges out of 83 children (46 boys and 37 girls, mean age 42±31.33 mo, median age 30 mo, range 12-162 mo.) referred for immediate reactions to egg were prospectively evaluated. DBPCFC with egg protein fractions were used in order to confirm the diagnosis of egg allergy. Sensitisation to egg was assessed by SPT with native egg white (fSPTew), native egg yolk (fSPTey) and commercial egg white (cSPTew) and yolk (cSPTey) preparations. Serum samples from 77 patients were analyzed for specific IgE antibodies to egg white (sIgEew) and yolk (sIgEey) using CAP system FEIA. Results. 28 challenges were positive, 23 to egg white and 5 to both egg white and yolk. None was positive to egg yolk alone. cSPTew were positive in 19/21 positive, and 34/58 negative, challenges with white. cSPTey were positive in 5/5 positive and in 37/74 negative challenges with yolk. fSPTew were positive in 20/21 positive, and in 34/53 negative, challenges with white. fSPTey were positive in 4/4 positive and in 39/68 negative challenges with yolk. sIgEew were positive in 19/24 positive challenges and in 25/53 negative challenges with egg white. sIgEey were positive in 1/3 positive challenges and in 17/69 negative challenges with egg yolk. These data generate NPV between 84.9 and 100% and PPV between 5.5 and 43.2%. Discussion: Egg allergy is essentially allergy to egg white, and none of the tests is able to predict a positive challenge with egg. The performance characteristics of the fresh allergens warrant their use for screening instead of the commercial reagents, with a preference in favour of fresh egg yolk, in selected populations. The differing accuracies between sIgEew and sIgEey indicate the latter as a screening tool in the general paediatric population (high spe and NPV). As a positive challenge with egg yolk is invariably associated with a positive challenge with egg white, we conclude that whole egg is satisfactory for diagnostic challenge. If well-separated from egg white (e.g., after boiling), eliminating egg yolk from the diet may not be necessary in all children with egg allergy.

↩

[153] - Takaoka Y, Ito K, Futamura M, Sakamoto T. Oral Food Challenge with Boiled Egg Yolk and Boiled and Raw Egg White. J Allergy Clin Immunol 2007;119(1 suppl):S192

RATIONALE: Some studies have shown that egg white displays reduced allergenicity on heating. We evaluated differences in clinical reactivity to boiled egg white, raw egg white and boiled egg yolk in egg allergy. METHODS: Oral food challenge was performed using boiled egg yolk (BEYFC), boiled egg white (BEWFC) and raw egg white (REWFC). Specific IgE levels to egg white, egg yolk and ovomucoid were measured using Immuno CAP. RESULTS: BEYFC was performed in 59 children, and only 2 patients (3.4%) displayed positive results. Among the 57 children who passed BEYFC, 22 failed BEWFC (39%). One patient with positive results for BEYFC passed BEWFC. BEWFC was performed in 349 children, and 233 children passed (66.8%). Prevalence of patients who failed BEWFC was increased in proportion to egg white-specific IgE level (0% for Class 0 and 1; 20.0% for Class 2; 40.1% for Class 3; 41.4% for Class 4; 38.5% for Class 5; 100% for Class 6). REWFC yielded positive results in 16 of 51 children who passed BEWFC or who were able to eat heated egg without symptoms (31.4%). CONCLUSIONS: BEYFC does not predict the probability of tolerating egg white. BEWFC is preferable before REWFC, as significant numbers of patients with raw egg allergy can consume boiled egg.

↩

[154] - Perackis K, Staden U, Mehl A, Niggemann B. Skin prick test with hen's egg: whole egg or egg white ? Allergy 2004;59:1236-1237

↩

[155] - Fiocchi A, Sarratud T, Martelli A, Terracciano L, Signoroni P. Allergy to egg white and allergy to egg yolk. EAACI 25th Congress, Vienna, 10-14 June, 2006, Poster n°576

Background Challenge with egg proteins is performed using whole egg extracts. However, allergising proteins of both white and yolk differ. Objective We sought to evaluate the response to white and yolk at challenge in a population of children presenting with symptoms attributed to egg. Methods 91 challenges out of 83 children (46 boys and 37 girls, mean age 42±31.33 mo, median age 30 mo, range 12-162 mo.) referred for immediate reactions to egg were prospectively evaluated. DBPCFC with egg protein fractions were used in order to confirm the diagnosis of egg allergy. Sensitisation to egg was assessed by SPT with native egg white (fSPTew), native egg yolk (fSPTey) and commercial egg white (cSPTew) and yolk (cSPTey) preparations. Serum samples from 77 patients were analyzed for specific IgE antibodies to egg white (sIgEew) and yolk (sIgEey) using CAP system FEIA. Results. 28 challenges were positive, 23 to egg white and 5 to both egg white and yolk. None was positive to egg yolk alone. cSPTew were positive in 19/21 positive, and 34/58 negative, challenges with white. cSPTey were positive in 5/5 positive and in 37/74 negative challenges with yolk. fSPTew were positive in 20/21 positive, and in 34/53 negative, challenges with white. fSPTey were positive in 4/4 positive and in 39/68 negative challenges with yolk. sIgEew were positive in 19/24 positive challenges and in 25/53 negative challenges with egg white. sIgEey were positive in 1/3 positive challenges and in 17/69 negative challenges with egg yolk. These data generate NPV between 84.9 and 100% and PPV between 5.5 and 43.2%. Discussion: Egg allergy is essentially allergy to egg white, and none of the tests is able to predict a positive challenge with egg. The performance characteristics of the fresh allergens warrant their use for screening instead of the commercial reagents, with a preference in favour of fresh egg yolk, in selected populations. The differing accuracies between sIgEew and sIgEey indicate the latter as a screening tool in the general paediatric population (high spe and NPV). As a positive challenge with egg yolk is invariably associated with a positive challenge with egg white, we conclude that whole egg is satisfactory for diagnostic challenge. If well-separated from egg white (e.g., after boiling), eliminating egg yolk from the diet may not be necessary in all children with egg allergy.

↩

[156] - Norgaard A, Bindslev-Jensen C, Skov PS, Poulsen LK. Specific serum IgE in the diagnosis of egg and milk allergy in adults. Allergy 1995;50:636-647

Levels of specific serum IgE to cow's milk, whole hen's egg, egg white, and egg yolk were compared to the outcome of double-blind, placebo-controlled food challenge (DBPCFC) with fresh egg and/or milk in 21 adults with a case history of immediate hypersensitivity to egg and/or milk. Specific serum IgE was measured by four different commercially available tests and by an inhouse Maxisorp RAST using freshly prepared food extracts. Sensitivities and negative predictive accuracies were generally high with egg white and milk, but low with egg yolk. Specificities and positive predictive accuracies were low for all allergens and tests. Changing the cutoff levels did not improve the ability of the tests to predict clinical allergy. Among commercially available test allergens, egg white gave the most consistent results in levels and class scores, and the highest degree of concordance with DBPCFC, whereas egg yolk and milk varied more. Applying freshly prepared food extracts in Maxisorp RAST did not improve diagnostic value. Measuring specific serum IgE levels in control subjects tolerant to egg/milk showed that false positive reactions occurred frequently among patients with another food allergy and atopic dermatitis, whereas most tests were likely to be negative in pollen-allergic and nonallergic volunteers. In conclusion, specific IgE measurements with egg white and milk were useful for exclusion of symptomatic hypersensitivity to egg and milk in patients with a positive history, whereas DBPCFC is still mandatory in patients with positive history and positive test. Measuring egg-yolk-specific IgE or using freshly prepared food extracts for specific IgE measurements added no further diagnostic information. The rate of clinically insignificant positive test results seems to be influenced by the prevalence of other food allergies and/or atopic dermatitis in the population under study.

↩

[157] - Boyano-Martinez T, Garcia-Ara C, Diaz-Pena JM, Munoz FM, Garcia Sanchez G, Martin-Esteban M. Validity of specific IgE antibodies in children with egg allergy. Clin Exp Allergy 2001;31:1464-1469

BACKGROUND: The demonstration of specific IgE antibodies to egg supports the existence of allergy to this food, but a correct diagnosis can only be obtained after a challenge test. Several studies have assessed different cut-off points in the level of these antibodies as predictors of clinical reactivity . OBJECTIVE: Validation of the specific IgE antibodies measured by the CAP System Fluorescence enzyme immunoassay (FEIA) technique in the diagnosis of egg allergy in children under 2 years of age . METHODS: A prospective study of 81 children with suspected egg allergy was performed. Specific IgE antibodies was quantified for egg white, egg yolk, ovoalbumin and ovomucoid. The diagnostic challenge test was carried out following the previously established criteria. The validity of the specific IgE antibodies was analysed using children with a negative diagnostic challenge test as control group . RESULTS: The prevalence of egg allergy in the group studied was 79% and egg white was the allergen that showed the greatest diagnostic efficacy. The sensitivity and positive predictive value of the prick test and of the CAP to egg white were excellent and the specificity and the negative predictive value had lower values. A level of > or = 0.35 KU(A)/L for specific IgE antibodies to egg white predicted the existence of reaction in 94% of the cases . CONCLUSIONS: Quantification of the specific IgE antibodies to egg white is useful in the diagnosis of egg allergy. In children under 2 years of age with a background of immediate hypersensitivity after egg ingestion and presence of specific IgE antibodies to egg white of > or = 0.35 KU(A)/L, diagnostic challenge test is not necessary to establish the diagnosis of allergy to this food.

↩

[158] - Monti G, Muratore MC, Peltran A, Bonfante G, Silvestro L, Oggero R, et al. High incidence of adverse reactions to egg challenge on first known exposure in young atopic dermatitis children: predictive value of skin prick test and radioallergosorbent test to egg proteins. Clin Exp Allergy 2002;32:1515-1519

↩

[159] - Rancé F, Fargeot-Espaliat A, Rittié JL, Micheau P, Morelle K, Abbal M. Valeur diagnostique du dosage des IgE spécifiques dirigées contre le blanc et le jaune d'œuf dans le diagnostic de l'allergie alimentaire à l'œuf de poule chez l'enfant. Rev Fr Allergol Immunol Clin 2003;43:369-372

L'objectif de l'étude est de définir les valeurs d'IgE spécifiques pour confirmer le diagnostic d'allergie à l'oeuf de poule avec une probabilité proche de 100 %. L'étude est conduite chez 185 enfants suspects d'allergie alimentaire vus consécutivement à l'hôpital des enfants de Toulouse. Un premier groupe est composé de 100 enfants dont l'allergie à l'oeuf est prouvée par un test de provocation par voie orale positif. Ces enfants sont comparés à un deuxième groupe de 85 enfants non allergiques à l'oeuf mais allergiques à un autre aliment, le plus souvent l'arachide. Tous les enfants ont bénéficié d'une exploration similaire : analyse clinique, prick test natif pour l'oeuf de poule (blanc et jaune), dosage des IgE sériques spécifiques pour le blanc et le jaune d'oeuf avec la technique Pharmacia Cap System, et test de provocation par voie orale. L'âge moyen des enfants est de 2,1 ans avec des extrêmes de 8 mois à 15 ans. Le diamètre moyen du prick test blanc d'oeuf est de 11,3 mm (extrêmes 0 à 25 mm) pour le groupe 1 et de 5,5 mm pour le groupe 2, p = 0,00001. La médiane des IgE spécifiques du blanc d'oeuf est plus élevée chez les allergiques à l'oeuf (22,5 kUA/L vs 0,76, p = 0,000001), comme la médiane des IgE jaune d'oeuf (6 kUA/L vs 0,35, p = 0,0001). Une concentration d'IgE blanc d'oeuf supérieure ou égale à 7,5 kUA/L est associée à une valeur prédictive positive de 100 % (valeur prédictive négative 68 %). Une concentration d'IgE jaune d'oeuf supérieure ou égale à 5,5 kUA/L est associée à une valeur prédictive positive de 100 % (valeur prédictive négative 52 %). Conclusion. - Notre étude objective une meilleure sensibilité des IgE blanc d'oeuf et une meilleure spécificité des IgE jaune d'oeuf. Les deux mesures sont utiles pour le diagnostic de l'allergie à l'oeuf de poule chez l'enfant. Des IgE blanc d'oeuf supérieures ou égales à 7,5 kUA/L et des IgE jaune d'oeuf supérieures ou égales à 5,5 kUA/L permettent de porter le diagnostic d'allergie à l'oeuf avec une probabilité proche de 100 %.

↩

[160] - Walsh BJ, Elliott C, Baker RS, Barnett D, Burley RW, Hill DJ, et al. Allergenic cross-reactivity of egg-white and egg-yolk proteins. An in vitro study. Int Arch Allergy Appl Immunol 1987;84:228-232

The radioallergosorbent test (RAST) and RAST inhibition test were used to examine cross-allergenicity amongst the major hen's egg-white and egg-yolk proteins. Using ovalbumin as a reference allergen to compare cross-reactivity, it was apparent that the proteins conalbumin, ovomucoid and lysozyme substantially inhibited binding to ovalbumin discs of IgE in the sera of patients clinically hypersensitive to egg. The converse situation with conalbumin, ovomucoid and lysozyme on the discs and ovalbumin as the inhibitor also resulted in significantly decreased levels of IgE binding to the proteins on the discs. It was also demonstrated that cross-reactions occurred between ovalbumin and the yolk protein, apovitellenin I. Cross-reaction was also observed surprisingly when egg lysozyme was on the disc and the milk protein allergen alpha-lactalbumin was used as the inhibitor. The demonstration of cross-reaction between all of these proteins may signify that there are a number of common allergenic determinants on these egg proteins, thus providing a molecular basis for the phenomenon of cross-reactivity.

↩

[161] - Anet J, Back JF, Baker RS, Barnett D, Burley RW, Howden MEH. Allergens in the white and yolk of hen's egg. Int Arch Allergy Appl Immunol 1985;77:364-371

The radioallergosorbent test (RAST) was used to compare the IgE binding of egg white and yolk, and allergenic proteins were detected by immunoelectrotransfer ('Western blotting'). The main allergens were found in egg white, but for a large proportion of the egg-sensitive patients, yolk contained specific IgE-binding constituents. For blood sera from 36 patients, there was a positive correlation between the results of RAST for egg white and for yolk. Lysozyme was found to be an allergen for some patients. The effect of heating on the allergenicity of egg white was examined and the allergenicity of hen egg white was compared with that of a duck egg. The allergens in yolk were associated with each of the three yolk fractions, and several of the proteins in the low-density lipoprotein fraction bound IgE.

↩

[162] - Langeland T. A clinical and immunological study of allergy to hen's egg white. Allergy 1983;38:399-412

The occurrence of proteins cross-reacting with allergens in hen's egg white was studied in turkey, duck, goose and seagull egg whites, in hen egg yolk, and in hen and chicken sera and flesh. The study was based upon quantitative immunoelectrophoretic techniques. The different egg whites were all found to contain proteins cross-reacting with most of the allergens in hen's egg white, but the degree of cross-reactivity varied considerably among the various egg whites. All egg whites contained proteins able to bind human IgE-antibody in the sera of patients with allergy to hen's egg white. Several proteins cross-reacting with allergens in hen's egg white were also detected in egg yolk and in hen and chicken sera and flesh. Clinical implications of the results are discussed.

↩

[163] - Walsh BJ, Elliott C, Baker RS, Barnett D, Burley RW, Hill DJ, et al. Allergenic cross-reactivity of egg-white and egg-yolk proteins. An in vitro study. Int Arch Allergy Appl Immunol 1987;84:228-232

The radioallergosorbent test (RAST) and RAST inhibition test were used to examine cross-allergenicity amongst the major hen's egg-white and egg-yolk proteins. Using ovalbumin as a reference allergen to compare cross-reactivity, it was apparent that the proteins conalbumin, ovomucoid and lysozyme substantially inhibited binding to ovalbumin discs of IgE in the sera of patients clinically hypersensitive to egg. The converse situation with conalbumin, ovomucoid and lysozyme on the discs and ovalbumin as the inhibitor also resulted in significantly decreased levels of IgE binding to the proteins on the discs. It was also demonstrated that cross-reactions occurred between ovalbumin and the yolk protein, apovitellenin I. Cross-reaction was also observed surprisingly when egg lysozyme was on the disc and the milk protein allergen alpha-lactalbumin was used as the inhibitor. The demonstration of cross-reaction between all of these proteins may signify that there are a number of common allergenic determinants on these egg proteins, thus providing a molecular basis for the phenomenon of cross-reactivity.

↩

[164] - Quirce S, Marañón F, Umpierrez A, De las Heras M, Fernández-Caldas E, Sastre J. Chicken serum albumin (Gal d 5) is a partially heat-labile inhalant and food allergen implicated in the bird-egg syndrome. Allergy 2001;56:754-762

BACKGROUND: Chicken serum albumin (alpha-livetin) has been implicated as the causative allergen of the bird-egg syndrome. However, the clinical relevance of sensitization to this allergen has not been confirmed by specific challenge tests and environmental sampling. We investigated whether chicken albumin can be detected in air samples collected in a home with birds, and whether sensitization to this protein may cause respiratory and food allergy symptoms. The heat resistance of chicken albumin and the possible cross-reactivity with conalbumin were also investigated . METHODS: We studied eight patients with food allergy to egg yolk who also suffered from respiratory symptoms (rhinitis and/or asthma) caused by exposure to birds. Sensitization to egg yolk and bird antigens was investigated by skin and serologic tests. Hypersensitivity to chicken albumin was confirmed by specific bronchial, conjunctival, and oral provocation tests . RESULTS: All patients had positive skin tests and serum IgE against egg yolk, chicken serum, chicken meat, bird feathers, and chicken albumin. The presence of airborne chicken albumin in the domestic environment was confirmed. Specific bronchial challenge to chicken albumin elicited early asthmatic responses in six patients with asthma. An oral challenge with chicken albumin provoked digestive and systemic allergic symptoms in the two patients challenged. IgE reactivity to chicken albumin was reduced by 88% after heating at 90 degrees C for 30 min. ELISA inhibition demonstrated only partial cross-reactivity between chicken albumin and conalbumin . CONCLUSION: Chicken albumin (Gal d 5) is a partially heat-labile allergen that may cause both respiratory and food-allergy symptoms in patients with the bird-egg syndrome.

↩

[165] - Walsh BJ, Hill DJ, Macoun P, Cairns D, Howden MEH. Detection of four distinct groups of hen egg allergens binding IgE in the sera of children with egg allergy. Allergol Immunopathol (Madr) 2005;33:183-191

Background: There appears to be a lack of agreement in the literature on the allergenicity of hen egg proteins. This may be partly due to the use of impure proteins in some cases. Egg yolk proteins have also been largely ignored in such studies. We therefore set out to determine, using especially purified proteins, their relative allergenicity, and to observe whether there were any relationships between their potency and the sensitivity of patients to them. Methods and results: The sera of 40 patients with clinically observed hen egg hypersensitivity were tested for specific IgE binding to purified egg white and egg yolk proteins using the radioallergosorbent test (RAST). Statistical treament by correspondence analysis of the percent radioactive uptakes in the RAST to the 8 proteins demonstrated that there were four distinct groups of patients reacting in a similar way to four discrete sets of proteins. CONCLUSIONS: The first three sets of allergens consisted of egg white proteins as follows: firstly, lysozyme and ovalbumin; secondly, ovomucoid; and thirdly, ovomucin..The fourth set contained the egg white protein ovotransferrin and the egg yolk proteins apovitellenins I and VI and phosvitin. The existence of patient groups may explain why various workers have reported different allergens to be important in egg hypersensitivity. A sufficiently large number of patients must be examined so as to give a representative distribution across each group, otherwise the results may be biased towards one allergen.

↩

[166] - Jarvinen KM, Beyer K, Vila L, Bardina L, Mishoe M, Sampson HA. Specificity of IgE antibodies to sequential epitopes of hen's egg ovomucoid as a marker for persistence of egg allergy. Allergy 2007;62:758-765

Background: Approximately two-thirds of egg-allergic infants become tolerant within the first 5 years of life. OBJECTIVE: We sought (1) to compare the recognition of sequential (linear) and conformational binding sites of ovomucoid, ovalbumin and ovotransferrin, by IgE antibodies of children with persistent and transient egg allergy, (2) to identify immunodominant IgE-and IgG-binding epitopes of ovomucoid, and (3) to compare epitope-specificity of IgE antibodies between patients with differing natural histories of egg allergy. METHODS: Using immunodot-blots or ImmunoCAPs, IgE-antibodies against conformational (native) and sequential (reduced and alkylated) egg proteins were determined at the time of clinical reactivity in patients who retained their allergy and in those who developed clinical tolerance. IgE- and IgG-binding epitopes were mapped for ovomucoid using overlapping decapeptides on SPOTs membranes. Recognition of the major IgE-binding epitopes were compared between patients with differing natural hi stories of egg allergy. RESULTS: The patients with long-lasting egg allergy had a higher concentrations of IgE antibodies against sequential and native ovomucoid and ovalbumin than the children who subsequently gained tolerance (P < 0.01). Four major IgE-binding epitopes were identified in ovomucoid at amino acid 1-10, 9-20, 47-56, and 113-124. IgE antibodies of all seven patients with persistent egg allergy recognized these epitopes whereas none of the 11 children who outgrew their egg allergy did so. CONCLUSIONS: Patients with persistent egg allergy develop IgE antibodies against more sequential and conformational epitopes of ovomucoid and ovalbumin. The presence of serum IgE antibodies to specific sequential epitopes of ovomucoid may be used as a screening instrument for persistent egg allergy

↩

[167] - Ando H, Movérare R, Kondo Y, Tsuge I, Tanaka A, Borres MP, et al. Utility of ovomucoid-specific IgE concentrations in predicting symptomatic egg allergy. J Allergy Clin Immunol 2008;122:583-588

Grass pollens are one of the most important airborne allergen sources worldwide. About 20 species from five subfamilies are considered to be the most frequent causes of grass pollen allergy, and the allergenic relationships among them closely follow their phylogenetic relationships. The allergic immune response to pollen of several grass species has been studied extensively over more than three decades. Eleven groups of allergens have been identified and described, in most cases from more than one species. The allergens range from 6 to 60 kD in apparent molecular weight and display a variety of physicochemical properties and structures. The most complete set of allergens has so far been isolated and cloned from Phleum pratense (timothy grass) pollen. Based on the prevalence of IgE antibody recognition among grass pollen-sensitized individuals, several allergens qualify as major, but members of two groups, groups 1 and 5, have been shown to dominate the immune response to grass pollen extract. Isoform variation has been detected in members of several of the allergen groups, which in some cases can be linked to observed genetic differences. N-linked glycosylation occurs in members of at least three groups. Carbohydrate- reactive IgE antibodies have been attributed to grass pollen sensitization and found to cross-react with glycan structures from other allergen sources, particularly vegetable foods. Another cause of extensive cross-reactivity are the group 12 allergens (profilins), which belong to a family of proteins highly conserved throughout the plant kingdom and present in all tissues. Members of eight allergen groups have been cloned and expressed as recombinant proteins capable of specific IgE binding. This development now allows diagnostic dissection of the immune response to grass pollen with potential benefits for specific immunotherapy.

↩

[168] - Lemon-Mule H, Sampson HA, Sicherer SH, Shreffler WG, Noone S, Nowak-Wegrzyn A. Immunologic changes in children with egg allergy ingesting extensively heated egg. J Allergy Clin Immunol 2008;122:977-983

BACKGROUND: Prior studies have suggested that heated egg might be tolerated by some children with egg allergy . OBJECTIVE: We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated . METHODS: Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg-tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg . RESULTS: Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg-reactive subjects had larger skin test wheals and greater egg white-specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg- and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels . CONCLUSIONS: The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

↩

[169] - Perry TT, Matsui EC, Conover-Walker MK, Wood RA. The relationship of allergen-specific IgE levels and oral food challenge outcome. J Allergy Clin Immunol 2004;114:144-149

Background Oral food challenges remain the gold standard for the diagnosis of food allergy. However, clear clinical and laboratory guidelines have not been firmly established to determine when oral challenges should be performed. Objective : We sought to determine the value of food-specific IgE levels in predicting challenge outcome. Method s : A retrospective chart review of 604 food challenges in 391 children was performed. All children had food-specific IgE levels measured by means of CAP-RAST before challenge. Data were analyzed to determine the relationship between food-specific IgE levels and challenge outcome, as well as the relationship between other clinical parameters and challenge outcome. Result s : Forty-five percent of milk challenges were passed compared with 57% for egg, 59% for peanut, 67% for wheat, and 72% for soy. Specific IgE levels were higher among patients who failed challenges than among those who passed (P .03 for each food). When seeking a specific IgE level at which a 50% pass rate could be expected, a cutoff level of 2 kUA/L was determined for milk, egg, and peanut. Data were less clear for wheat and soy. Coexistent eczema or asthma was associated with failed egg challenges, but other atopic disease was otherwise not associated with challenge outcome. Conclusions : Allergen-specific IgE concentrations to milk, egg, and peanut and, to a lesser extent, wheat and soy serve as useful predictors of challenge outcome and should be considered when selecting patients for oral challenge to these foods.

↩

[170] - Knight AK, Shreffler W, Sampson HA, Sicherer SH, Noone S, Nowak-Wegrzyn A. Evaluation of Prick Skin Tests (PSTs) to Predict the Outcome of Double-Blind, Placebo-Controlled Food Challenge (DBPCFC) to Egg When Egg-Specific Serum IgE Is Low. J Allergy Clin Immunol 2005;115(2 suppl.):S55

RATIONALE: When egg-specific serum IgE is low (< 2-6 kIU/L), and particularly as it declines to undetectable, the risk of a reaction declines, but not to zero. We sought to determine if PSTs can differentiate children with low egg-IgE who pass or fail a DBPCFC to egg METHODS: Egg-IgE levels, PSTs, and DBPCFC outcomes of 48 eggallergic children were analyzed with nonparametric statistics in a retrospective study. PSTs were performed with bifurcated needles using commercial extracts and reported as mean wheal diameter RESULTS: Children who passed (n=13; 27%) egg-DBPCFC compared to those who failed (n=35; 73%) did not differ significantly regarding age (median 4.0 vs. 5.3 yrs; p=0.14) or egg-IgE (median egg-IgE level 0.45 vs 0.62 kU/L; p=0.25). When egg-IgE was <0.7 kU/L, 38% of children passed egg-DBPCFC. There were statistically significant (p= 0.039) but small differences between egg-PST sizes for children who passed (median, 4 mm; range 0 to 9 mm) compared to those who failed (median 5 mm; range, 0 to 8 mm). Children with wheal size <3 mm where more likely to pass than those with a wheal > 6 mm (50% vs. 14%) CONCLUSIONS: In children with low egg-IgE, those with smaller PST wheals to egg were more likely to pass egg-DBPCFC than those with larger PSTs, but there was considerable overlap in wheal size between the groups. To obtain more generalizeable data, prospective studies that include large groups of subjects with a wide range of clinical features and laboratory results, but employ uniform PST methodology, are needed

↩

[171] - Knight AK, Shreffler WG, Sampson HA, Sicherer SH, Noone S, Mofidi S, et al. Skin prick test to egg white provides additional diagnostic utility to serum egg white-specific IgE antibody concentration in children. J Allergy Clin Immunol 2006;117:842-847

BACKGROUND: Levels of IgE antibody to egg white of greater than 7 kIU/L are highly predictive of clinical reactivity to egg, and lower levels often require evaluation with oral food challenge (OFC) to establish definitive diagnosis. OFCs have inherent risks, and diagnostic criteria indicating high likelihood of passing would be clinically useful . OBJECTIVE: We sought to determine whether the size of the skin prick test (SPT) to egg white adds diagnostic utility for children with low egg white-specific IgE antibody levels . METHODS: A retrospective analysis of clinical history, egg white-specific IgE antibody levels, SPT responses, and egg OFC outcomes was performed . RESULTS: Children who passed (n = 29) egg OFCs and those who failed (n = 45) did not differ significantly in age, clinical characteristics, or egg white-specific IgE levels. There were, however, significant differences between both egg white SPT wheal response size and egg/histamine SPT wheal index. Children who failed egg OFCs had a median wheal of 5.0 mm; those who passed had a median wheal of 3.0 mm (P = .003). Children who failed egg OFCs had a median egg/histamine index of 1.00; those who passed had a median index of 0.71 (P = .001). For egg white-specific IgE levels of less than 2.5 kIU/L, an SPT wheal of 3 mm or an egg/histamine index of 0.65 was associated with a 50% chance of passing . CONCLUSION: In children with low egg white-specific IgE levels, those with smaller SPT wheal responses to egg were more likely to pass an egg OFC than those with larger wheal responses. The size of the egg white SPT response might provide additional information to determine the timing of egg OFC. CLINICAL IMPLICATIONS: The size of the egg white SPT wheal response might provide the clinician with additional information to determine the timing of egg OFC in children with low egg white-specific IgE antibody levels.

↩

[172] - Shek LPC, Soderstrom L, Ahlstedt S, Beyer K, Sampson HA. Determination of food specific IgE levels over time can predict the development of tolerance in cow's milk and hen's egg allergy. J Allergy Clin Immunol 2004;114:387-391

Background The majority of children with cow's milk and hen's egg allergy develop clinical tolerance with time. However, there are no good indices to predict when and in whom this occurs. Objective The aim of this study was to determine if monitoring food specific IgE levels over time could be used as a predictor for determining when patients develop clinical tolerance. Methods Eighty-eight patients with hen's egg and 49 patients with cow's milk allergy who underwent repeated double-blind, placebo-controlled food challenges were included in the study. Using the Pharmacia CAP-System FEIA, specific IgE (sIgE) levels to cow's milk and hen's egg were retrospectively determined from stored serum samples obtained at the time of the food challenges. Logistic regression was used to evaluate the relationship between tolerance development and the decrease in sIgE levels over a specific time period between the two challenges. Results Twenty-eight of the 66 egg-allergic and 16 of the 33 milk-allergic patients lost their allergy over time. For egg, the decrease in sIgE levels (P=.0014) was significantly related to the probability of developing clinical tolerance, with the duration between challenges having an influence (P=.06). For milk there also was a significant relationship between the decrease in sIgE levels (P=.0175) and the probability of developing tolerance to milk but no significant contribution with regard to time. Stratification into 2 age groups, those below 4 years of age and those above 4 years of age at time of first challenge, had an effect, with the younger age group being more likely to develop clinical tolerance in relation to the rate of decrease in sIgE. The median food sIgE level at diagnosis was significantly less for the group developing „tolerance‰ to egg (P < .001), and a similar trend was seen for milk allergy (P=.06). Using these results, we developed a model for predicting the likelihood of developing tolerance in milk and egg allergy based on the decrease in food sIgE over time. Conclusion We found that the rate of decrease in food sIgE levels over time was predictive for the likelihood of developing tolerance in milk and egg allergy. Using the likelihood estimates from this study could aid clinicians in providing prognostic information and in timing subsequent food challenges, thereby decreasing the number of premature and unnecessary double-blind, placebo-controlled food challenges

↩

[173] - Thong BYH, Hourihane JOB. Monitoring of IgE-mediated food allergy in chidhood. Acta Paediatr 2004;93:759-764

"BACKGROUND: The prevalence of IgE-mediated food allergy (FA) in childhood varies from 6% to 8% in the first year of life compared to 1% to 2% in adults. In contrast to adults, FA in childhood, often part of the ""allergic march"", resolves in more than 85% of children, especially those with hypersensitivity to cow's milk and egg. AIM: This paper explains the rationale for continuing care for childhood FA and describes how children should be monitored for resolution/persistence of FA . METHODS: A clinical, multidisciplinary approach and management algorithm based on relevant, peer-reviewed original research articles and reviews using the keywords anaphylaxis, atopic eczema, children, milk allergy, double-blind placebo-controlled food challenge, egg allergy, epinephrine, failure to thrive, food allergy, food challenge, food hypersensitivity, immunoglobulin E, nutrition, natural history, paediatrics, peanut allergy, prevalence, psychosocial factors, quality of life, radioallergosorbent test, and tolerance from years 1966 to 2003 in MEDLINE. Additional studies were identified from article reference lists . RESULTS: A combination of outcome measures, a multidisciplinary approach involving a dietitian and allergy nurse specialist, and a management algorithm are useful tools in clinical management . CONCLUSIONS: Prospective studies of non-selected children, optimally from birth cohorts, are needed to evaluate the effects of such management programmes regarding FA in childhood."

↩

[174] - Niggemann B, Celik-Bilgili S, Ziegert M, Reibel S, Sommerfeld C, Wahn U. Specific IgE levels do not indicate persistence or transience of food allergy in children with atopic dermatitis. J Investig Allergol Clin Immunol 2004;14:98-103

BACKGROUND: Food allergy in early childhood usually resolves with time; however, little is known about predictors for persistence or transience of food allergy in children with atopic dermatitis. The aim of the study was to evaluate whether specific IgE levels in serum could be a useful predictor of the outcome of oral re-challenges . METHODS: In 74 children, 99 oral food challenges were performed (cow milk n = 48, hen egg n = 37, and wheat n = 14) and repeated after a median time interval of 16 months. In 15 of the 74 children, a third challenge (n = 22) could be performed, with a median time interval from second challenge to third challenge of 15 months . RESULTS: There were 37 children with transient food allergy (positive first challenge and negative second challenge), while 62 children had persistent food allergy (positive first challenge and negative second challenge). Comparison of the two groups showed that specific IgE as well as total IgE in serum was significantly higher in the latter group. However, looking at the time course, specific IgE did not decrease significantly during elimination diet . CONCLUSION: Our results indicate that specific IgE in serum--although very helpful at the time of the first diagnosis--cannot predict whether a chid will become tolerant after a period of avoidance. Therefore, oral re-challenges remain mandatory.

↩

[175] - Villard-Truc F, Gomez SA, Deschildre A, Rancé F. Test de provocation par voie orale aux aliments chez l'enfant. Quand, pour qui et comment? 2- Sélection des patients. Rev Fr Allergol Immunol Clin 2006;46:610-624

↩

[176] - Lemon-Mule H, Sampson HA, Sicherer SH, Shreffler WG, Noone S, Nowak-Wegrzyn A. Immunologic changes in children with egg allergy ingesting extensively heated egg. J Allergy Clin Immunol 2008;122:977-983

BACKGROUND: Prior studies have suggested that heated egg might be tolerated by some children with egg allergy . OBJECTIVE: We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated . METHODS: Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg-tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg . RESULTS: Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg-reactive subjects had larger skin test wheals and greater egg white-specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg- and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels . CONCLUSIONS: The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

↩

[177] - Ando H, Movérare R, Kondo Y, Tsuge I, Tanaka A, Borres MP, et al. Utility of ovomucoid-specific IgE concentrations in predicting symptomatic egg allergy. J Allergy Clin Immunol 2008;122:583-588

Grass pollens are one of the most important airborne allergen sources worldwide. About 20 species from five subfamilies are considered to be the most frequent causes of grass pollen allergy, and the allergenic relationships among them closely follow their phylogenetic relationships. The allergic immune response to pollen of several grass species has been studied extensively over more than three decades. Eleven groups of allergens have been identified and described, in most cases from more than one species. The allergens range from 6 to 60 kD in apparent molecular weight and display a variety of physicochemical properties and structures. The most complete set of allergens has so far been isolated and cloned from Phleum pratense (timothy grass) pollen. Based on the prevalence of IgE antibody recognition among grass pollen-sensitized individuals, several allergens qualify as major, but members of two groups, groups 1 and 5, have been shown to dominate the immune response to grass pollen extract. Isoform variation has been detected in members of several of the allergen groups, which in some cases can be linked to observed genetic differences. N-linked glycosylation occurs in members of at least three groups. Carbohydrate- reactive IgE antibodies have been attributed to grass pollen sensitization and found to cross-react with glycan structures from other allergen sources, particularly vegetable foods. Another cause of extensive cross-reactivity are the group 12 allergens (profilins), which belong to a family of proteins highly conserved throughout the plant kingdom and present in all tissues. Members of eight allergen groups have been cloned and expressed as recombinant proteins capable of specific IgE binding. This development now allows diagnostic dissection of the immune response to grass pollen with potential benefits for specific immunotherapy.

↩

[178] - Lemon-Mule H, Sampson HA, Sicherer SH, Shreffler WG, Noone S, Nowak-Wegrzyn A. Immunologic changes in children with egg allergy ingesting extensively heated egg. J Allergy Clin Immunol 2008;122:977-983

BACKGROUND: Prior studies have suggested that heated egg might be tolerated by some children with egg allergy . OBJECTIVE: We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated . METHODS: Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg-tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg . RESULTS: Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg-reactive subjects had larger skin test wheals and greater egg white-specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg- and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels . CONCLUSIONS: The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

↩

[179] - Konstantinou GN, Giavi S, Kalobatsou A, Vassilopoulou E, Douladiris N, Saxoni-Papageorgiou P, et al. Consumption of heat-treated egg by children allergic or sensitized to egg can affect the natural course of egg allergy: Hypothesis generating observations. J Allergy Clin Immunol 2008;122:414-415

↩

[180] - Lidman PGL, Watson WTA, Simons FER, Becker AB. Reactions to Food in Children Recurs After Negative Oral Challenge. AAAAI 60th Annual Meeting, San Francisco, 19-23 March 2004, Poster n°492

Rationale To determine if patients sensitized to food remain tolerant after negative food challenge. Methods We assessed children who had allergic reactions, positive epicutaneous skin test, and/or positive capFEIA to peanut, egg or milk and subsequently had a negative food challenge between 1996 to 2003. Families were contacted by phone and questioned as to the frequency of ingestion of the food(s) in question and if any further reactions had occurred. Results There were 302 children <16 years of age with negative food challenges during this period. We randomly reviewed 107 patients (35%) with 121 challenges. 14 (12%) <6 months from challenge were excluded. 28 (23%) were lost to follow-up. Complete data were available for 59 (47%). 40/59 (68%) regularly ate the food with no problem. 4/59 (7%) subsequently reacted, all with egg (4/18; 22%), and all to raw or less well cooked egg; 1/4 completely avoided egg and 3/4 tolerated egg in baked goods. In spite of no reaction, 2/26 previously peanut allergic continued to completely avoid peanut and 10/26 had peanut < weekly. All 15 patients with negative milk challenge tolerated and continued to regularly consume milk. Conclusions Subjects with negative egg challenge were more likely to react again than subjects with negative peanut or milk challenge. Peanut allergy remains a concern for many patients, even with a negative challenge. Allergists should consider a second challenge for egg and/or peanut allergic patients.

↩

[181] - Guerin-Dubiard C, Pasco M, Molle D, Desert C, Croguennec T, Nau F. Proteomic analysis of hen egg white. J Agric Food Chem 2006;54:3901-3910

Hen egg white is an original biological fluid in which major proteins have been widely studied, unlike the minor components. In this study, two-dimensional electrophoresis associated with mass spectrometry enabled the separation of 69 protein spots and their matching with major proteins, which were already known, and with minor proteins. Sixteen proteins were identified, and among them, two had never been previously detected in hen egg white, i.e., Tenp, a protein with strong homology with a bacterial permeability-increasing protein family (BPI), and VMO-1, an outer layer vitelline membrane protein. Thirteen proteins present a very wide polymorphism (ovotransferrin, ovomucoid, clusterin, etc.), some of them up to nine isoforms (ovoinhibitor). Eleven functional protein families were identified (serpin, transferrin, protease inhibitors Kazal, glycosyl hydrolases, lipocalin, bactericidal permeability-increasing protein, clusterin, UPAR/CD59/Ly6/ snake neurotoxin, cysteine protease inhibitor, VMO-1, and folate receptor families). These various biological functions could be interesting for further valorizations. In addition, three spots remain unidentified, probably because these proteins are not yet indexed in the international protein databanks.

↩

[182] - Fötisch K, Vieths S. N- and O-linked oligosaccharides of allergenic glycoproteins. Glycoconj J 2001;18:373-390

Cross-linking of cell-bound IgE on mast cells or basophils by polyvalent antigens causes the release of histamine and other mediators of the allergic response which then lead to the development of allergic symptoms. In this event not only peptide epitopes, but also carbohydrates can act as cross-linking elements. Since peptide epitopes of allergens are subject of most published studies, this review is focused on glycosidic epitopes. The current knowledge of the structures and possible epitopes of oligosaccharides linked to allergenic glycoproteins is briefly reviewed, showing that complex plant N-glycans containing alpha1,3 fucose and beta1,2 xylose are most frequently involved in the structures of IgE epitopes. In own studies a prevalence of up to 29% anti-glycan IgE was determined among pollen-allergic patients. The clinical relevance of these carbohydrate specific IgE antibodies is still a matter of controversial discussions Cross-linking of cell-bound IgE on mast cells or basophils by polyvalent antigens causes the release of histamine and other mediators of the allergic response which then lead to the development of allergic symptoms. In this event not only peptide epitopes, but also carbohydrates can act as cross-linking elements. Since peptide epitopes of allergens are subject of most published studies, this review is focused on glycosidic epitopes. The current knowledge of the structures and possible epitopes of oligosaccharides linked to allergenic glycoproteins is briefly reviewed, showing that complex plant N-glycans containing alpha1,3 fucose and beta1,2 xylose are most frequently involved in the structures of IgE epitopes. In own studies a prevalence of up to 29% anti-glycan IgE was determined among pollen-allergic patients. The clinical relevance of these carbohydrate specific IgE antibodies is still a matter of controversial discussions.

↩

[183] - Besler M, Steinhart H, Paschke A. Allergenicity of hen's egg-white proteins: IgE binding of native and deglycosylated ovomucoid. Food Agric Immunol 1998;9:277-288

Ovomucoid (OM) is a major allergen of hen's egg white. Carbohydrate moieties from the glycoprotein were removed by chemical deglycosylation. Deglysocylated ovomucoid (d-OM) consists of 5 isoforms with mol. wt. (MW) between 20.7 and 21.5 kDa, whereas native OM has a MW of 28 kDa as determined by matrix-assisted laser desorption/ionization time of flight MS. The IgE-binding properties of both proteins were investigated. All patients' sera tested, showed strong IgE binding to both native OM and d-OM in SDS-PAGE/immunoblot. In enzyme-allergosorbent test experiments, 50% inhibition of IgE binding was observed, at almost the same inhibitor concn. of 67 and 57 ng ml-1 for native OM and d-OM, respectively. Results indicate that only epitopes on the protein backbone are responsible for IgE binding while carbohydrate residues do not participate in allergenic structures of OM

↩

[184] - Cooke SK, Sampson HA. Allergenic properties of ovomucoid in man. J Immunol 1997;159:2026-2032

Ovomucoid, the dominant allergen in hen's egg, is a highly glycosylated protein comprising 186 amino acids arranged in three tandem domains (Gal d 1.1, 1.2, and 1.3). The purpose of this study was to evaluate the allergenic properties of ovomucoid. The three ovomucoid domains were isolated and evaluated with sera from egg allergic patients to determine B cell domain specificity, B cell epitopes, and the relative importance of linear and conformational structures and carbohydrate chains to B cell epitopes. Peripheral blood T cells from egg allergic patients were used to evaluate T-dominant domains and reactivity to reduced and oxidized ovomucoid. There was significantly more IgE activity to the second ovomucoid domain (median percentage of ovomucoid-specific IgE: Gal d 1.2, 40%; Gal d 1.1, 23%; Gal d 1.3, 26%). Quantities of patient IgG Ab were comparable for all three domains. Five IgE and seven IgG binding regions were identified. IgE Ab binding to reduced ovomucoid and IgG binding to oxidized ovomucoid were significantly reduced compared with that to native ovomucoid (28 and 69%, respectively). Peripheral blood T cells of 21 of 33 patients reacted to Gal d 1.3, 18 of 33 reacted to Gal d 1.2, and 18 of 33 reacted to Gal d 1.1. T cell proliferation in vitro in response to reduced and oxidized ovomucoid were significantly greater than that in response to the native protein. These results indicate a dichotomy between T and B cell domain dominance, and the presence of both unique and common IgE and IgG epitopes. Furthermore, the results suggest that conformational B cell epitopes play a more significant role in ovomucoid allergenicity than previously appreciated, and that carbohydrate moieties have a minor effect on allergenicity.

↩

[185] - Malandain H, Giroux F, Cano Y. The influence of carbohydrate structures present in common allergen sources on specific IgE results. Eur Ann Allergy Clin Immunol 2007;39:216-220

BACKGROUND: Cross-reactive carbohydrate determinants (CCD) are well known interferants in specific IgE assays (sIgE). Glyco-epitopes are not restricted to CCD and extracts used to prepare in vitro tests contain many other glycoproteins able to bind glycan-specific IgE. The overall amounts of IgE-bindable glycan structures in allergen sources are unknown . OBJECTIVE: We aimed at quantifying the influence of N-glycan structures on IgE reactivity to commonly tested allergen sources . METHODS: IgE reactivity to 51 allergen extracts, one purified natural allergen and 10 recombinant allergens was measured on Phadia UniCAP system using 2 sera demonstrating significant levels of glycan-related IgE reactivity. Immobilized bromelain and horseradish peroxidase (HRP) were used to capture N-glycan-specific IgE from these sera. Residual IgE reactivity was measured for 42 allergen sources and 4 recombinant/purified allergens . RESULTS: An obviously excessive number of positive CAP-results were obtained with both sera, especially for plant-based allergen sources. Capture of glycan-specific IgE led to a decrease of serum IgE ractivity, variable among allergen sources and between sera. Among others, peanut results were proven largely interfered by the presence of glycan-specific IgE. Unexpectedly some allergen sources showed a slight influence of glycan-related reactivity, such as cockroach, mosquito, mussel, shrimp and domestic mites . CONCLUSION: In patients sensitized to pollens or to Hymenoptera venoms sIgE results should be interpreted with caution. One cannot substract the result of a glyco-reporter test (bromelain and/or HRP) in order to compute glycan-free slgE results for common allergen sources like peanuts. As long as the demonstration of a significant role for glycan structures in clinical allergic reactions is lacking, a simple pre-treatment able to discard glycan-specific IgE from serum would be useful to improve accuracy of in vitro diagnostic tests.

↩