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Le céleri

vendredi 4 juin 2010, par Allerdata


Le céleri est le principal aliment du syndrome “ bouleau-armoise-Apiacées.


On retrouve des prévalences de positivité très élevées pour le bouleau (40 à 100%) et/ou pour l’armoise (50 à 100%) parmi les patients sélectionnés sur la base d’une allergie au céleri .

Le lien entre sensibilisation pollinique et allergie au céleri s’explique par la présence d’allergènes homologues à ceux du céleri dans le bouleau (PR-10 et profiline) et dans l’armoise (profiline).

  • La PR-10 de céleri est Api g 1 , la profiline est Api g 4 .
  • Il est très vraisemblable que l’armoise contient aussi un autre (ou d’autres) allergène(s) croisant avec le céleri.
  • Une hypothèse serait la présence dans le pollen d’armoise d’une protéine homologue d’Api g 5 .
  • Api g 5 est une protéine glycosylée de 55-58 kDa dont l’IgE-réactivité semble limitée à ses chaînes glucidiques . Certains fragments d’Api g 5 présentent une homologie avec des enzymes à FAD comme Phl p 4 (fléole) ou Cyn d 4 (chiendent digité) .

La sensibilisation pollinique induit la réactivité vis à vis du céleri .

  • Ceci est visible dans la dissymétrie des réactions croisées bouleau-céleri ou armoise-céleri : l’inhibition du pollen par le céleri est souvent incomplète, contrairement à l’inhibition du céleri par le pollen .
  • Le lien entre armoise et céleri est attesté par TPO chez patients mono-polliniques à l’armoise .
  • De plus, Bohle a montré que l’activation des cellules T était plus efficace avec Bet v 1 qu’avec Api g 1 .

Si bouleau et armoise sont manifestement associés à une réactivité pour le céleri, d’autres pollens peuvent ajouter leur part dans la sensibilisation du patient vis-à-vis des profilines . C’est le cas des graminées qui, dans certaines régions, sont plus souvent positives que le bouleau ou l’armoise chez les allergiques aux Apiacées .

Le rôle des profilines est moins bien établi que celui des PR-10.

  • Des réactions cliniques avec le céleri sont rencontrées dans des régions dépourvues de bouleaux .
  • En Allemagne, les sujets polliniques au bouleau présentent une réactivité pour Api g 1, mais ceux qui sont polliniques à l’armoise aussi ont une fréquente réactivité pour les profilines en blot (15 kDa) . Cela est visible particulièrement dans les séries de patients polliniques à l’armoise mais pas au bouleau .

L’allergie au céleri peut donc se présenter avec une réactivité vis à vis d’Api g 1 (PR-10), d’Api g 4 (profiline) ou d’Api g 1 et Api g 4.

  • Pauli estime que l’allergénicité du céleri est supérieure en cas de pollinose à l’armoise plutôt qu’au bouleau isolément .
  • Cela rejoint les constatations de Wüthrich pour qui la cuisson affecte plus la réactivité du céleri chez les sujets bouleau-céleri que chez les sujets armoise-céleri .
  • De même Bauer note que 7 fois sur 9 une réaction systémique avec le céleri associe armoise et bouleau.

Cette allergénicité accrue liée à l’armoise pourrait trouver sa cause dans la présence d’allergènes croisants jusque-là non caractérisés, notamment parmi les protéines de poids moléculaire élevé (“ HMW ”) .

Parmi les différentes formes sous lesquelles le céleri est consommé, le tubercule (racine) semble plus allergisant que les feuilles , certains patients n’étant allergiques qu’au tubercule .

  • Le céleri en tant qu’épice provient de la racine séchée et broyée et donne aussi des réactions comme le céleri-rave cru .
  • Cependant, aucun cas d’allergie au sel de céleri n’a été relevé dans les statistiques du CICBAA .

Le céleri est la cause de réactions cliniques parfois très sévères . En Suisse, près de la moitié des réactions au céleri sont systémiques .

Une anaphylaxie induite par l’effort , ou par l’aspirine a été rapportée. Dans les deux cas les patients avaient une pollinose à l’armoise.

Le Réseau d’Allergo-Vigilance avait relevé en mai 2010 40 cas pour le céleri (sur 900 déclarations), ce qui place le céleri en 5 ème position parmi les causes d’allergies alimentaires sévères.

L’allergie au céleri est liée également aux habitudes alimentaires locales. Par exemple, le céleri-rave n’est pas consommé en Italie .

Céleri et stabilité à la cuisson et à la digestion

La cuisson diminue fortement la réactivité au céleri chez les sujets sensibilisés essentiellement aux PR-10 (Api g 1), donc chez les patients polliniques au bouleau mais pas à l’armoise .

  • Ceci est du à l’instabilité des PR-10 à la chaleur. Après chauffage, Api g 1 ne se refolde pas normalement .
  • Wüthrich montre que les TC natifs sont négativés après cuisson chez 12/13 patients mono-bouleau contre seulement 6/27 des armoise ou armoise+bouleau .
  • De même, Ballmer-Weber observe que parmi 6 patients avec TPODA encore positif avec le céleri après cuisson, 5 sont positifs pour les profilines et/ou des protéines de haut poids moléculaire .
  • Cette réactivité au céleri cuit peut provenir d’Api g 5, dont on sait la grande résistance à la chaleur. Pour Bublin, cela est en lien avec la glycosylation d’Api g 5 .

On a donc, en simplifiant, des patients bouleau, Api g 1, tolérants après cuisson, et des patients armoise, allergiques après cuisson aussi et présentant volontiers des réactions plus sévères.

Le mode de cuisson pourrait ne pas être indifférent aussi dans l’évolution de l’allergénicité du produit :

  • Wüthrich a montré, par exemple, qu’en cas de cuisson dans l’eau, cette dernière éluait des allergènes présents dans le céleri et que l’eau de cuisson était elle-même capable de donner des TC positifs . Cela n’est pas neutre dans les cas où l’eau de cuisson est ingérée (soupes).

Contrairement au chauffage, le séchage, l’irradiation ou les hautes pressions ne modifient pas l’IgE-réactivité du céleri .

Le devenir de l’IgE-réactivité des allergènes de céleri au cours de la digestion intestinale a été insuffisamment étudié.

  • On peut supposer que la PR-10, Api g 1 est rapidement détruite, tandis que la profiline, Api g 4, a une résistance modérée.
  • Mais il semblerait que, globalement, le céleri présente une assez bonne résistance à la digestion tant stomacale qu’intestinale .
  • Il est possible que cela soit du à des allergènes HMW, notamment parce que ces derniers s’avèrent souvent correspondre aux composants glycosylés du céleri.

Céleri et CCD

(voir aussi : Les CCD)

Le céleri semble avoir une place particulière dans la question, non encore résolue, de la relevance clinique des épitopes glucidiques IgE-réactifs.

En effet, la fréquence des réactivités in vitro de type CCD chez les patients allergiques au céleri est élevée, de l’ordre de 25 à 50% .

Par ailleurs :

  • Fötisch montre que le complexe MUXF-BSA (chaînes glucidiques + bovalbumine) est capable de générer une histaminolibération chez un patient allergique au céleri
  • Lüttkopf observe un TPODA positif pour le céleri chez un sujet positif uniquement pour des CCD
  • Bublin remarque que l’histaminolibération induite par Api g 5 n’est pas reproduite si Api g 5 est présenté sous forme déglycosylée ,
  • et dans le même travail, il est montré que MUXF-BSA et Api g 5 (non déglycosylé) inhibent des bandes HMW tant dans le céleri que dans l’armoise.

Ces résultats font estimer par certains experts que, du moins chez quelques patients, les épitopes glucidiques pourraient avoir une relevance clinique .

Mais la récente étude Europrevall sur le céleri aboutit à une conclusion contraire  : aucune stimulation cellulaire n’a pu être obtenue avec Api g 5 dans un test RBL (Rat Basophil Leukemia) pour 8 patients CAP positifs nApi g 5 et présentant une allergie au céleri attestée par TPODA.

La présence d’une réactivité de type CCD dans le sérum des patients impose donc une certaine prudence dans l’interprétation des tests in vitro pour le céleri .

Apport des tests in vitro pour le diagnostic d’une allergie au céleri

S’il a été cherché d’améliorer le diagnostic in vitro à l’aide de tests cellulaires , l’intérêt s’est porté très tôt sur l’utilisation des allergènes recombinants .

Le concept d’un diagnostic moléculaire (“ component-resolved diagnosis ”) a été appliqué au céleri et les premiers résultats en ont récemment été présentés dans le cadre du projet européen Europrevall .

Trois molécules ont été testées : rApi g 1 (PR-10), rApi g 4 (profiline) et la protéine naturelle purifiée nApi g 5. Le diagnostic d’allergie au céleri était confirmé par TPODA. Les 24 patients (Allemagne) étaient polliniques au bouleau, la plupart aux graminées et/ou à l’armoise :

  • La sensibilité diagnostique de rApi g 1 était de 75%, avec une spécificité de 65%. Ces chiffres rejoignent ceux déjà publiés pour des patients également polliniques au bouleau .
  • rApi g 1 présentait une meilleure sensibilité que le CAP céleri (67%), mais était moins spécifique (= plus souvent positif chez les 20 polliniques au bouleau sans allergie au céleri)
  • La positivité pour rApi g 1 et/ou rApi g 4 et/ou nApi g 5 portait la sensibilité à 87%. Mais cela au prix d’une spécificité de 55% seulement

Ce travail n’a donc pas montré une amélioration décisive du diagnostic in vitro avec l’usage de tests basés sur des allergènes purs/recombinants plutôt que sur l’extrait classique (CAP céleri).

Par ailleurs, aucun de ces 3 allergènes ne permettait de différencier une réponse clinique limitée à la sphère orale d’une réponse systémique :

  • positivité pour rApi g 1 : syndrome oral 7 patients, réaction systémique 10 patients
  • pour rApi g 4 : 5 vs 5
  • pour nApi g 5 : 6 vs 4

On pourra cependant remarquer 2 points à partir des résultats de cette étude (cf. figures ci-dessous) :

  • il n’existe pas de bonne corrélation entre rBet v 1 et rApi g 1. Bien que Bet v 1 soit a priori l’initiateur de la réactivité à Api g 1, les patients reconnaissent des épitopes sur Api g 1 qui sont parfois différents de ceux reconnus sur Bet v 1
  • il existe par contre une bonne corrélation entre le glyco-reporter MUXF-BSA et nApi g 5 : la réactivité à ce dernier semble donc n’être que l’image de la réactivité CCD chez ces patients, laquelle est fortement liée aux graminées (7 patients CCD positifs sur les 9 qui ont un CAP fléole > 30 kU/l).
[1] - Vallier P, Dechamp C, Vial O, Deviller P. A study of allergens in celery with cross-sensitivity to mugwort and birch pollens. Clin Allergy 1988;18:491-500
Sixty-one sera with positive RAST to mugwort pollen (Artemisiae vulgaris) were submitted to RASTs for birch pollen (Betula verrucosa) and celery (Apium graveolens). In 36 cases RAST results were positive for celery. In addition, 23 sera presented specific IgE to birch pollen. The binding of specific IgE to individual allergens in celery, mugwort pollen and birch pollen was studied by the immunoblotting technique. This involved electrophoretic separation of allergenic extracts, electrotransfer of proteins onto nitrocellulose sheets and sensitive immunoenzymatic detection. Eighteen sera had specific IgE binding to two celery components of molecular weight around 15 kD. All these sera also detected a 15 kD allergen in mugwort and two allergens in birch of 14 kD and 16 kD molecular weight. The sera that did not detect the 15 kD bands in celery failed to react with both the 15 kD mugwort component and the 14 and 16 kD birch components. Specific cross-inhibitions of the detection of these allergens on immunoblots were obtained by pre-incubation of the sera with crude extract of the three species. These results strongly suggest that such allergens display some structural identity and that they could be at the origin of some cases of crossed hypersensitivity to celery, mugwort pollen and birch pollen
[2] - Bauer L, Ebner C, Hirschwehr R, Wüthrich B, Pichler C, Fritsch R, et al. IgE cross-reactivity between birch pollen, mugwort pollen and celery is due to at least three distinct cross-reacting allergens: immunoblot investigation of the birch-mugwort-celery syndrome. Clin Exp Allergy 1996;26:1161-1170
Allergy to celery is often associated with sensitization to birch and/or mugwort pollen. OBJECTIVE and METHODS: In a multi-centre study, sera from 23 patients suffering from type 1 allergy to celery and 15 patients with positive celery RAST but no clinical sensitization were compared. To examine whether cross-reactivity between celery and mugwort pollen includes cross-sensitization to birch pollen allergens, we determined cross-reacting structures in birch pollen, mugwort pollen and celery by means of immunoblotting. Inhibition studies were performed by preincubation of sera with extracts of birch pollen, mugwort pollen, and celery. RESULTS: We identified three groups of proteins--homologues of Bet v 1 and birch profilin (Bet v 2) as well as a group of proteins with a molecular range of 46 to 60 kD--displaying IgE-cross-reactivity, which were shared by birch pollen and celery. Two of these groups of allergens (profilin and the 46 to 60 kD proteins) were also present in mugwort pollen. In this paper we demonstrate that most cross-reacting allergens present in mugwort pollen and celery can also be detected in birch pollen extract. CONCLUSION: Therefore we propose, from a serological point of view, to extend the mugwort-celery syndrome to the birch-mugwort-celery syndrome.
[3] - Wüthrich B, Hofer T. [Food allergy: the celery-mugwort-spice syndrome. Association with mango allergy ?]. Dtsch Med Wochenschr 1984;109:981-986
Celery allergies are commonly observed in mugwort pollen-allergic patients. This situation is frequently associated with an allergy to spices of the umbelliferous family. Thus a "celery-mugwort-spice syndrome" has been established. In 31 patients (27 females, 4 males) allergy to celery was diagnosed between 1978 and 1982. They were followed up in 1983 and complementary tests (skin and RAST) with various raw vegetables, spices and mugwort pollen were done. For specific diagnosis of allergy to celery skin testing (scratch or prick) with fresh celery bulb was reliable. In contrast, RAST was not sufficiently sensitive, 87% of patients allergic to celery had pollinosis in the form of mugwort pollen sensitisation established by skin testing and RAST. Allergy to carrots was clinically and by testing currently associated in 52%. In contrast, a clinically relevant hypersensitivity to caraway (26%), parsley (16%), fennel (13%), green pepper (10%) and aniseed (3%) was found less frequently although these allergens showed a much larger positivity in skin testing. This signifies group sensitisation within the umbelliferous plants. The association of celery-mugwort allergy with allergy to mango fruit described here for the first time cannot be explained as group sensitisation within a botanic relation, as mango, and pistachio-nut, belong to the family of anacardiaceae.
[4] - Fötisch K, Altmann F, Haustein D, Vieths S. Involvement of carbohydrate epitopes in the IgE response of celery-allergic patients. Int Arch Allergy Immunol 1999;120:30-42
This study was performed to get further insights into antibody responses to cross-reactive carbohydrate determinants (CCD), including initial experiments to prove the biological activity of anti-CCD IgE. Earlier studies have shown that IgE specific for CCD occurs in about 25% of celery-allergic patients. The clinical significance of these antibody specificities is doubtful. METHODS: Patient sera were selected on the basis of a positive case history of celery allergy and multiple binding to high molecular weight celery allergens on immunoblots. Specific IgE to native and heated celery tuber was determined by the enzyme allergosorbent test (EAST). N-glycans were purified after extensive digestion of specific glycoproteins, such as pineapple stem bromelain, bovine fibrin, and human IgG, and used as antigens in an IgE ELISA as well as in EAST and immunoblotting inhibition experiments. Dose-related histamine release was performed with BSA neoglycoproteins containing 3-4 units of the purified glycopeptides. RESULTS: Seven celery-allergic patients were identified who clearly presented IgE against the N-glycan purified from bromelain which is a common structure within the plant kingdom. Chemical defucosylation showed that alpha1, 3-fucose is a key structure for IgE binding. In patients with anti-CCD IgE, the maximal inhibition of celery EAST by the bromelain glycan ranged from 22 to 100%. Inhibition of celery immunoblots by preincubation of patient serum with this glycan led to a quenching of multiple bands at masses >40 kD. After linking the bromelain glycopeptide to BSA, a strong dose-related histamine release was obtained in a celery-allergic patient, occurring at lower concentrations than with the recombinant major protein allergen from celery, Api g 1. CONCLUSIONS: Our results demonstrate that IgE specific for CCD is common in celery-allergic patients, and can represent the major proportion of IgE against this food. alpha1, 3-fucose was confirmed to be an essential part of the IgE epitope. Immunoblotting inhibition indicated the presence of this carbohydrate determinant on multiple glycoproteins in celery extract. Although histamine release was only performed in 1 patient, our data show that proteins carrying multiple glycan units can be biologically active in patients sensitized to CCD.
[5] - Mittag D, Vieths S, Vogel L, Wagner-Loew D, Starke A, Hunziker P, et al. Birch pollen-related food allergy to legumes: identification and characterization of the Bet v 1 homologue in mungbean (Vigna radiata), Vig r 1. Clin Exp Allergy 2005;35:1049-1055
BACKGROUND: Recently allergic reactions to legumes mediated by Bet v 1-homologous food allergens were described for soy and peanut. In this study we assessed allergic reactions to another legume, to mungbean seedlings, and identified its Bet v 1-homologous allergen Vig r 1 . METHODS: Ten patients were selected who had a history of allergic reactions to mungbean seedlings and a respiratory allergy to birch pollen. The Bet v 1 homologue in mungbean seedlings, Vig r 1, was cloned by a PCR strategy, expressed in Escherichia coli, and purified by preparative SDS-PAGE. In all sera, specific IgE against birch pollen, Bet v 1, Bet v 2, Vig r 1, and the Bet v 1 homologues in soy (Gly m 4) and cherry (Pru av 1) was determined by CAP-FEIA. Cross-reactivity of specific IgE with Vig r 1, Bet v 1, Gly m 4, and Pru av 1 was assessed by immunoblot inhibition. Expression of Vig r 1 during development of mungbean seedlings and under wounding stress was analysed by immunoblotting. The Vig r 1 double band was analysed by matrix-assisted laser desorption/ionization time-of-flight and liquid chromatography/tandem mass spectrometry (LC/MS/MS) . RESULTS: All patients were sensitized to birch pollen and Bet v 1, 20% to Bet v 2, and 90% to Gly m 4. Seventy percent of the patients showed IgE binding to a double band at 15 kDa in mungbean extract that was inhibited after pre-incubation of sera with rBet v 1. PCR cloning revealed that the mungbean homologue of Bet v 1 had a molecular weight of 16.2 kDa, a calculated pI of 4.6% and 42.8% amino acid sequence identity with Bet v 1. MS analysis confirmed similarity of the double band with the deduced Vig r 1 sequence, but also indicated the existence of other Vig r 1 isoforms. ImmunoCAP analysis detected IgE against Vig r 1 in 80% of the sera. IgE binding to Vig r 1 was inhibited with Gly m 4 in six of six and with rPru av 1 in four of six patients. Vig r 1 expression occurred during development of seedlings and was increased by wounding stress . CONCLUSIONS: Food allergy to mungbean seedlings can be caused by primary sensitization to birch pollen and is mediated by Vig r 1 in the majority of the patients with birch pollen-related allergy to mungbean seedlings.
[6] - Ballmer-Weber BK, Vieths S, Lüttkopf D, Heuschmann P, Wüthrich B. Celery allergy confirmed by double-blind, placebo-controlled food challenge: a clinical study in 32 subjects with a history of adverse reactions to celery. J Allergy Clin Immunol 2000;106:373-378
BACKGROUND: Celery root is a frequent cause of food allergy in pollen-sensitized patients. Because of problems in blinding challenges with fresh vegetables and the risk of anaphylactic reactions, no double-blind, placebo-controlled, food challenges (DBPCFCs) with celery have been published so far . OBJECTIVE: The aim of the study was to confirm the clinical relevance of celery as a food allergen by DBPCFCs and to evaluate current diagnostic procedures in patients with true allergy . METHODS: DBPCFCs were performed in 32 patients with a history of an allergic reaction to celery. The patients underwent skin prick tests (SPTs) with celery extracts, crude celery, and different pollen extracts. Specific IgE for celery was determined by using the CAP method . RESULTS: Twenty-two of 32 patients had a positive DBPCFC result. Two patients reacted to placebo, and 8 patients did not respond to the challenge. Of the nonresponders, 4 reacted to an open provocation with celery. The sensitivity of CAP determination for specific IgE (> or =0.7 kU/L) to celery in patients with a positive DBPCFC result was 73%, 48% to 86% for SPTs (> or =3 mm) with commercial extracts, and 96% for prick-to-prick tests with crude celery. The positive predictive value of the SPT and CAP tests was between 87% and 96%, whereas the specificity and negative predictive values were poor . CONCLUSION: This study confirms the importance of celery as a food allergen for use in DBPCFCs. The SPT and CAP methods proved to be reliable for the diagnosis of a relevant allergy to celery in regard to sensitivity and positive predictive value but not to specificity and negative predictive value.
[7] - Kleine-Tebbe J, Wangorsch A, Vogel L, Crowell DN, Haustein UF, Vieths S. Severe oral allergy syndrome and anaphylactic reactions caused by a Bet v 1-related PR-10 protein in soybean, SAM22. J Allergy Clin Immunol 2002;110:797-804
BACKGROUND: Anaphylactic reactions to soy products have been attributed to stable class 1 food allergens . OBJECTIVE: IgE- mediated reactions to a soy-containing dietary food product in patients allergic to birch pollen were investigated . METHODS: Detailed case histories were taken from 20 patients. Their sera were analyzed for IgE (UniCAP) specific for birch, grass, mugwort, the recombinant birch allergens rBet v 1 and rBet v2, and soy protein. Extracts from birch pollen, soy isolate, rBet v 1, and the recombinant PR-10 soy protein rSAM22 were coupled to paper disks or nitrocellulose for IgE measurements (enzyme allergosorbent test) or Western blot analysis. Enzyme allergosorbent testing, Western blot inhibition, and histamine release studies were performed with the same allergens . RESULTS: Most patients (17/20) experienced facial, oropharyngeal, and/or systemic allergic symptoms within 20 minutes after ingesting the soy product for the first time. Birch pollen allergy (16/20) was common, along with oral allergy syndrome to apple (12/20) or hazelnut (11/20). IgE levels to birch and Bet v 1 but not to other inhalants were high in 18 of 20 patients. Significant IgE binding to rSAM22 occurred in 17 of 20 patients. Blot experiments with the soy isolate revealed IgE-binding bands at 17 kd (15/20), 22 kd (1/20), and 35 to 38 kd (2/20); the former was inhibited by preincubation of the sera with rBet v 1 or rSAM22. Birch extract and soy isolate, rBet v 1, and rSAM22 induced dose-dependent histamine release in the nanomolar range . CONCLUSION: Immediate-type allergic symptoms in patients with birch pollen allergy after ingestion of soy protein-containing food items can result from cross-reactivity of Bet v 1 -specific IgE to homologous pathogenesis-related proteins, particularly the PR-10 protein SAM22.
[8] - Pauli G, Bessot JC, Dietemann-Molard A, Braun PA, Thierry R. Celery sensitivity: clinical and immunological correlations with pollen allergy. Clin Allergy 1985;15:273-279
The authors studied twenty patients with celery allergy and concomitant hypersensitivity to certain pollens (mugwort, birch). The specific symptoms induced by eating celery were attacks of urticaria and angio oedema (seventeen out of twenty) respiratory complaints (eight out of twenty), systemic anaphylaxis with vascular collapse (three out of twenty). A strong association between clinical reactions to celery and mugwort sensitization, and to a lesser degree between celery allergy and birch pollen sensitization was established. Celery allergy is mediated by IgE antibodies and can be easily diagnosed by cutaneous tests using fresh material and/or by adequate RAST test. RAST inhibitions performed on individual sera suggest the existence of common antigens in celery and mugwort, and in celery and birch pollen. However, the exact nature of these common antigens has not yet been determined.
[9] - Hoffmann-Sommergruber K, Demoly P, Crameri R, Breiteneder H, Ebner C, Laimer Da Camara Machado M, et al. IgE reactivity to Api g 1, a major celery allergen, in a Central European population is based on primary sensitization by Bet v 1. J Allergy Clin Immunol 1999;104:478-484
BACKGROUND: Up to 70% of patients with tree pollen allergy display allergic symptoms when eating certain fruits and vegetables. Homologous proteins with allergenic features are present in a wide range of plant species and can cause allergic reactions. OBJECTIVE: The aim of this study was to evaluate recombinant Api g 1, a major celery allergen, for in vivo and in vitro diagnosis of celery allergy in populations from Davos, Switzerland, and Montpellier, France. METHODS: A group of patients with celery and birch pollen allergy from Davos was tested, and the results from those tests were compared with results from a group of patients allergic to celery from Montpellier. Skin prick tests were performed with a commercial celery extract, crude celery, and purified recombinant Api g 1. Quantitative and qualitative serology was done with natural and recombinant allergens by means of RASTs and immunoblotting. RESULTS: Recombinant Api g 1 allowed accurate in vivo diagnosis of celery allergy in all patients from the Swiss group. RAST results with celery extract were negative in 8 of 24 patients; results of immunoblotting with celery extract were negative in 4 of 24 patients, and results of immunoblotting with recombinant (r)Api g 1 were negative in 8 of 24 patients. In the French group 11 of 12 patients had a positive skin reaction with crude celery extract, but only 2 patients reacted with rApi g 1. RAST results for celery were positive in 8 of 12 patients. In immunoblotting experiments 8 patient sera displayed IgE directed against various celery allergens, whereas no patients sera had rApi g 1-specific IgE. CONCLUSION: Our results document that rApi g 1 allows accurate in vivo diagnosis only in areas where birch trees are common. In areas where no birch trees grow, primary sensitization takes place through different pollen allergens (eg, mugwort pollen). Moreover, it became evident that birch pollen and celery allergy are highly related in Central Europe, whereas in Southern Europe the mugwort-celery type is predominant.
[10] - Ebner C, Hirschwehr R, Bauer L, Breiteneder H, Valenta R, Ebner H, et al. Identification of allergens in fruits and vegetables: IgE cross-reactivities with the important birch pollen allergens Bet v 1 and Bet v 2 (birch profilin). J Allergy Clin Immunol 1995;95:962-969
In this study serum samples collected from 20 patients with birch pollen allergy were investigated. All patients had experienced allergic symptoms after contact with or ingestion of particular fresh fruits and vegetables known as birch pollen-related foods. METHODS: Serum samples were tested by means of immunoblotting for IgE reactivities with proteins in extracts of birch pollen, apple, pear, celery, carrot, and potato. Anti-Bet v 1 and anti-Bet v 2 antibodies were used to investigate cross-reactivity. Inhibition studies were performed by preincubation of sera with recombinant Bet v 1 and Bet v 2. RESULTS: IgE binding to proteins, corresponding to the major birch pollen allergen Bet v 1 and to Bet v 2 (birch pollen profilin) could be observed. An allergen homologous to Bet v 1 could be detected in apple, pear, and celery when a Bet v 1-specific monoclonal antibody was used. Testing a polyclonal rabbit anti-Bet v 2 antibody with extracts of the respective plants revealed the presence of profilins in every source tested. Inhibition with recombinant Bet v 1 and Bet v 2 led to complete blocking or marked reduction of IgE binding to proteins of comparable molecular weights in the respective food extracts, indicating IgE cross-reactivity. CONCLUSION: Our results indicate that many plant-derived food agents contain proteins with high homology to the birch pollen allergens Bet v 1 and Bet v 2 and must therefore be considered as potentially threatening for patients with tree pollen allergy.
[12] - Hoffmann-Sommergruber K, Ferris R, Pec M, Radauer C, O'Riordain G, Laimer Da Camara Machado M, et al. Characterization of Api g 1.0201, a new member of the Api g 1 family of celery allergens. Int Arch Allergy Immunol 2000;122:115-123
The association of pollinosis with allergy to plant foods occurs in up to 70% of tree pollen-allergic patients. In recent years, some of the relevant cross-reacting proteins have been characterized at the molecular and immunological level. Api g 1 has been identified as the celery homologue of the major birch pollen allergen, Bet v 1. Although a number of Bet v 1 isoforms have been characterized from birch pollen, little is known about isoforms of food allergens and their allergenic features. METHODS: Api g 1.0201, an isoform of Api g 1, was isolated from a cDNA library, cloned and sequenced. The cDNA was expressed in Escherichia coli and the purified recombinant protein was tested in immunoblots. RESULTS: Api g 1.0201 displays 72% sequence similarity to the previously identified Api g 1.0101 and consists of 159 amino acid residues. The sequence of Api g 1.0201 has five additional amino acid residues at the carboxy-terminus as compared to Api g 1.0101. Purified recombinant Api g 1.0201 is recognized by IgE from the sera of celery-allergic patients, as well as by the murine monoclonal anti-Bet v 1 antibody. In general, this isoform displays a weaker IgE-binding capacity than Api g 1.0101, as concluded from immunoblotting experiments. Results from inhibition assays revealed that IgE-binding to Api g 1.0201 is only slightly reduced by preincubation with either purified recombinant Api g 1.0101 or purified recombinant Bet v 1a. Total inhibition was only achieved when using purified natural Bet v 1. CONCLUSIONS: At present, little is known about the IgE-binding capacity of isoforms of Bet v 1 homologues of food allergens. Identification and characterization of such isoforms may help to contribute to a better understanding of food allergy and the observed cross-reactivity to pollen allergy
[13] - Scheurer S, Wangorsch A, Haustein D, Vieths S. Cloning of the minor allergen Api g 4 profilin from celery (Apium graveolens) and its cross-reactivity with birch pollen profilin Bet v 2. Clin Exp Allergy 2000;30:962-971
Profilin is a panallergen that is recognized by IgE from about 20% of birch pollen- and plant food-allergic patients. A subgroup of celery-allergic patients shows IgE-reactivity with this minor allergen. To investigate the IgE-binding potential and cross-reactivity of celery profilin at the molecular level, this study was aimed at the cloning and immunological characterization of this allergen. OBJECTIVES: Cloning, expression and purification of profilin from celery tuber to characterize its immunological properties and its cross-reactivity with birch pollen profilin. METHODS: Cloning of celery profilin was performed by polymerase chain reaction using degenerated primers and a 5'RACE method for the identification of the unknown 5'-end of the cDNA. Expression was carried out in Escherichia coli BL21 (DE3) using a modified vector pET-30a. The recombinant profilin was purified by affinity chromatography on poly L-proline coupled to sepharose. Immunological characterization was performed by immunoblotting, EAST and IgE-inhibition experiments. RESULTS: The coding region of the cDNA of celery profilin was identified as a 399-bp open reading frame, coding for a protein of 133 amino acids with a calculated molecular weight of 14.3 kDa. The deduced amino acid sequence of the corresponding protein showed high identity with other plant profilins (71-82%) recently described as allergens. Celery profilin was isolated as highly pure nonfusion protein. The IgE-reactivity of celery profilin was similar to that of natural protein. Seven of 17 celery-allergic patients tested presented specific IgE-antibodies to the recombinant protein tested by immunoblotting. Inhibition experiments showed high cross-reactivity of IgE with both profilins from celery and birch pollen. Moreover, the biological activity of recombinant celery profilin was demonstrated by a histamine release assay. CONCLUSIONS: Celery profilin is an important allergenic compound in celery and shows high homology to birch pollen profilin, Bet v 2. According to the revised IUIS allergen nomenclature, we suggest naming the celery profilin Api g 4. In addition to the cross-reacting major allergens Api g 1 and Bet v 1, birch pollinosis and associated allergies to celery can therefore additionally be explained by the cross-reactivity between homologous profilins. Moreover, recombinant Api g 4 may be used for target-specific diagnosis and structural analyses
[14] - Grote M, Stumvoll S, Reichelt R, Lidholm J, Valenta R. Identification of an allergen related to Phl p 4, a major timothy grass pollen allergen, in pollens, vegetables, and fruits by immunogold electron microscopy. Biol Chem 2002;383:1441-1445
Group 4 grass pollen allergens represent 60 kDa glycoproteins recognized by 70% of patients sensitive to these pollens. An antiserum against purified Phl p 4 from timothy grass pollen was used to investigate various pollens, fruits, and vegetables for Phl p 4-related allergens by immunogold electron microscopy. In timothy grass, mugwort, and birch pollens, allergens were located in the wall, and in timothy grass and birch pollens additionally in the cytoplasm. In peanut, apple, celery root, and carrot root, only cytoplasmic areas were labeled. Group 4-related allergens thus occur in pollens of unrelated plants and in plant food and may therefore contribute to crossreactivities in patients allergic to various pollens and plant food.
[15] - Marknell DeWitt A, Andersson K, Peltre G, Lidholm J. Cloning, expression and immunological characterization of full-length timothy grass pollen allergen Phl p 4, a berberine bridge enzyme-like protein with homology to celery allergen Api g 5. Clin Exp Allergy 2006;36:77-86
BACKGROUND: Timothy grass pollen is a common cause of respiratory allergy in the temperate regions. The major group 4 allergen, Phl p 4, has previously been purified and studied biochemically and immunologically, but has so far not been produced and characterized as a recombinant protein . OBJECTIVE: To clone and characterize timothy grass pollen allergen Phl p 4 . METHODS: Full-length Phl p 4 cDNA was cloned using a PCR-based strategy including 3'-and 5'-RACE. Recombinant Phl p 4 was expressed in Escherichia coli and purified by immobilized metal ion affinity chromatography. Its immunological activity was investigated using experimental ImmunoCAP tests, sera from Phl p 4 sensitized individuals and Phl p 4 reactive polyclonal and monoclonal animal antibodies . RESULTS: Five full-length Phl p 4 cDNA clones were analysed. Sequence deviations between the clones were present at nine amino acid positions, and the consensus sequence comprised an open reading frame of 525 amino acids, including a predicted 25-residue signal peptide. The calculated molecular weight of the deduced mature protein was 55.6 kDa and the isoelectric point 9.9, both consistent with previously observed properties of purified nPhl p 4. Close sequence similarity was found to genomic clones from several other Pooideae grass species and to Bermuda grass pollen allergen BG60. Further, similarity was found to members of the berberine bridge enzyme (BBE) family, including celery allergen Api g 5. Recombinant Phl p 4 bound specific immunoglobulin (Ig)E from 31 of 32 nPhl p 4-reactive sera, and the IgE binding to rPhl p 4 could be inhibited by nPhl p 4 in a dose-dependent manner . CONCLUSIONS: Full-length Phl p 4 cDNA was cloned and showed sequence similarity to members of the BBE family. Recombinant Phl p 4 was produced and shared epitopes with natural Phl p 4.
[16] - Ganglberger E, Radauer C, Grimm R, Hoffmann-Sommergruber K, Breiteneder H, Scheiner O, et al. N-terminal sequences of high molecular weight allergens from celery tuber. Clin Exp Allergy 2000;30:566-570
Celery tuber is an important source of food allergens. Low molecular weight celery allergens were identified as homologues of Bet v 1 and profilin. Little is known about the relevant allergens with molecular weights between 45 and 60 kDa, which cross-react with other plant food and pollen allergens. OBJECTIVE: The aim of this study was to isolate cross-reactive, high molecular weight allergens from celery and to characterize them by N-terminal sequencing. METHODS: High molecular weight allergens of celery were identified by immunoglobulin (Ig) E immunoblotting with patients' sera, and the IgE-binding patterns were compared with those of the monoclonal antibirch pollen antibody BIP3, as well as of a polyclonal rabbit anti-Art v 1 antiserum. Two independent methods, elution from preparative SDS-PAGE or anion exchange chromatography, were used to purify the IgE-binding celery proteins of interest. The isolated proteins were examined by N-terminal sequencing and IgE-immunoblots. RESULTS: Celery allergens with molecular masses of 55, 58 and 63 kDa, which were also recognized by the monoclonal BIP3 antibody and a polyclonal anti-Art v 1 antiserum, were isolated. The 63-kDa allergen was N-terminally blocked. The 55- and 58-kDa compounds yielded the same N-terminus, which showed no homology to known proteins in the databases. CONCLUSION: The combination of two independent protein separation techniques, immunoblotting and N-terminal sequencing, identified an N-terminus of two allergens in the 60-kDa molecular weight region. Our data will be helpful for the definite molecular characterization of these important cross-reactive molecules.
[17] - Bublin M, Radauer C, Wilson IB, Kraft D, Scheiner O, Breiteneder H, et al. Cross-reactive N-glycans of Api g 5, a high molecular weight glycoprotein allergen from celery, are required for immunoglobulin E binding and activation of effector cells from allergic patients. FASEB J 2003;17:1697-1699
Allergy diagnosis relying on the determination of specific IgE is frequently complicated by the presence of cross-reacting IgE of unclear clinical relevance. Particularly, the anaphylactogenic activity of IgE directed to cross-reactive carbohydrate moieties of glycoproteins from plants and invertebrates has been a matter of debate. In this study, we present the biochemical and immunological characterization of Api g 5, a glycoprotein allergen from celery with homology to FAD containing oxidases. Carbohydrate analysis of the allergen revealed the presence of glycans carrying fucosyl and xylosyl residues, structures previously shown to bind IgE. Chemical deglycosylation of the protein completely abolished binding of serum IgE from all 14 patients tested. Likewise, basophils from a patient allergic to mugwort pollen and celery were stimulated only by native Api g 5, whereas the deglycosylated allergen did not trigger release of histamine. IgE inhibition immunoblots showed that native Api g 5 other than the deglycosylated protein completely inhibited IgE binding to high molecular weight allergens in protein extracts from birch pollen, mugwort pollen, and celery. A similar inhibition was accomplished using the IgE binding oligosaccharide, MUXF, coupled to bovine serum albumin. All these observations taken together confer convincing evidence that IgE directed to cross-reactive carbohydrates is capable of eliciting allergic reactions in vivo.
[18] - Marknell DeWitt A, Andersson K, Peltre G, Lidholm J. Cloning, expression and immunological characterization of full-length timothy grass pollen allergen Phl p 4, a berberine bridge enzyme-like protein with homology to celery allergen Api g 5. Clin Exp Allergy 2006;36:77-86
BACKGROUND: Timothy grass pollen is a common cause of respiratory allergy in the temperate regions. The major group 4 allergen, Phl p 4, has previously been purified and studied biochemically and immunologically, but has so far not been produced and characterized as a recombinant protein . OBJECTIVE: To clone and characterize timothy grass pollen allergen Phl p 4 . METHODS: Full-length Phl p 4 cDNA was cloned using a PCR-based strategy including 3'-and 5'-RACE. Recombinant Phl p 4 was expressed in Escherichia coli and purified by immobilized metal ion affinity chromatography. Its immunological activity was investigated using experimental ImmunoCAP tests, sera from Phl p 4 sensitized individuals and Phl p 4 reactive polyclonal and monoclonal animal antibodies . RESULTS: Five full-length Phl p 4 cDNA clones were analysed. Sequence deviations between the clones were present at nine amino acid positions, and the consensus sequence comprised an open reading frame of 525 amino acids, including a predicted 25-residue signal peptide. The calculated molecular weight of the deduced mature protein was 55.6 kDa and the isoelectric point 9.9, both consistent with previously observed properties of purified nPhl p 4. Close sequence similarity was found to genomic clones from several other Pooideae grass species and to Bermuda grass pollen allergen BG60. Further, similarity was found to members of the berberine bridge enzyme (BBE) family, including celery allergen Api g 5. Recombinant Phl p 4 bound specific immunoglobulin (Ig)E from 31 of 32 nPhl p 4-reactive sera, and the IgE binding to rPhl p 4 could be inhibited by nPhl p 4 in a dose-dependent manner . CONCLUSIONS: Full-length Phl p 4 cDNA was cloned and showed sequence similarity to members of the BBE family. Recombinant Phl p 4 was produced and shared epitopes with natural Phl p 4.
[19] - Breiteneder H, Hoffmann-Sommergruber K, O'Riordain G, Susani M, Ahorn H, Ebner C, et al. Molecular characterization of Api g1, the major allergen of celery (Apium graveolens), and its immunological and structural relationships to a group of 17 kDa tree pollen allergens. Eur J Biochem 1995;233:484-489
Individuals suffering from immediate hypersensitivity (type-I allergy) to a particular pollen frequently display intolerance to several foods of plant origin. In this respect, individuals sensitized to birch pollen and/or mugwort pollen frequently display type-I allergic symptoms after ingestion of celery. In this study, we expressed the major allergenic protein of celery, Api g 1, which is responsible for the birch-celery syndrome, in the form of a non-fusion protein. The open reading frame of the cDNA of Api g 1 codes for a protein of 153 amino acids with a molecular mass of 16.2 kDa and 40% identity (60% similarity) to the major allergen of birch pollen, Bet v 1. Furthermore, Api g 1 exhibited similar characteristics to (a) two proteins in parsley induced by fungal infection, (b) the major tree pollen allergens and (c) pathogenesis-related and stress-induced proteins in other plant species. The reactivity of recombinant Api g 1 with IgE antibodies present in sera from celery intolerant patients was comparable to that of the natural celery allergen. Cross-reactivity with Bet v 1 was proven by cross-inhibition experiments, which provides further support for the existence of the birch-celery syndrome and for the suggestion that allergies to some vegetable foods are epiphenomena to allergies caused by inhalation of tree pollen.
[20] - Wüthrich B, Stäger J, Johansson SG. Celery allergy associated with birch and mugwort pollinosis. Allergy 1990;45:566-571
Skin prick tests (SPT) with various celery, carrot and potato preparations (raw, cooked, cooking water of each vegetable and allergen extracts) as well as specific IgE determinations by RAST to celery mix, celeriac (or root celery), stick celery and heated celery extracts were performed in 70 patients with positive prick or intracutaneous tests to birch and/or mugwort pollens and celery (extract and/or raw). 94% of the patients showed positive prick tests to raw celeriac, 36% to cooked celeriac and 8/13 to cooking water. Celery-birch positive patients (n = 13) showed negative or low RASTs to heated celery extracts and to stick celery. By contrast, in the celery-mugwort sensitive patients (n = 6) the celery RASTs with heated celery extracts remained clearly positive and high RAST values to stick celery could be found. Celery-birch-mugwort-association (n = 22) favoured more positive results with relatively high values of RAST to celeriac. The results of homologous and heterologous RAST inhibition experiments with birch, mugwort, unheated and heated celery (100 degrees C) carried out in nine celery-RAST positive sera are also discussed.
[21] - Pauli G, Bessot JC, Dietemann-Molard A, Braun PA, Thierry R. Celery sensitivity: clinical and immunological correlations with pollen allergy. Clin Allergy 1985;15:273-279
The authors studied twenty patients with celery allergy and concomitant hypersensitivity to certain pollens (mugwort, birch). The specific symptoms induced by eating celery were attacks of urticaria and angio oedema (seventeen out of twenty) respiratory complaints (eight out of twenty), systemic anaphylaxis with vascular collapse (three out of twenty). A strong association between clinical reactions to celery and mugwort sensitization, and to a lesser degree between celery allergy and birch pollen sensitization was established. Celery allergy is mediated by IgE antibodies and can be easily diagnosed by cutaneous tests using fresh material and/or by adequate RAST test. RAST inhibitions performed on individual sera suggest the existence of common antigens in celery and mugwort, and in celery and birch pollen. However, the exact nature of these common antigens has not yet been determined.
[22] - Osterballe M, Hansen TK, Mortz CG, Bindslev-Jensen C. The clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults. Allergy 2005;60:218-225
BACKGROUND: Previous studies have described cross-reactivity between fresh fruits, vegetables and pollen. However, no data demonstrates the clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults with and without symptoms in the pollen season . OBJECTIVE: The aim of this study was to estimate the clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults and to examine the diagnostic value of skin-prick test (SPT), histamine release and specific IgE compared with the outcome of oral challenge . METHODS: In total, 936 unselected adults (female : male 479 : 457, median age 33.7 years) were examined for pollen sensitization and clinical cross-reactivity with pollen-related fruits and vegetables by questionnaire, SPT, histamine release, specific IgE and oral challenge . RESULTS: The prevalence of pollen sensitization was 23.8% (n = 223). The probability of a clinical reaction to pollen-related foods in the respective pollen-sensitized groups was: 24% (birch), 4% (grass), 10% (mugwort), 35% (birch + grass), 8% (grass + mugwort) and 52% (birch + grass + mugwort). The odds ratio of a clinical reaction to pollen-related fruits and vegetables in symptomatic pollen-sensitized adults was as high as four times (birch + grass) the odds ratio of a clinical reaction in asymptomatic pollen-sensitized adults . CONCLUSION: This study not only demonstrates a high prevalence of clinical reactions to fruits and vegetables in pollen-sensitized adults, but also a discrepancy between the prevalence of sensitization to fruits and vegetables and the clinical relevance in different pollen-sensitized groups with symptoms in the pollen season as a significant factor.
[23] - Bohle B, Radakovics A, Jahn-Schmid B, Hoffmann-Sommergruber K, Fischer GF, Ebner C. Bet v 1, the major birch pollen allergen, initiates sensitization to Api g 1, the major allergen in celery: evidence at the T cell level. Eur J Immunol 2003;33:3303-3310
Due to IgE cross-reactivity, birch pollen-allergic individuals frequently develop type I hypersensitivity reactions to celery tuber. We evaluated the T cell response to the major allergen in celeriac, Api g 1, and the cellular cross-reactivity with its homologous major allergen in birch pollen, Bet v 1. Api g 1-specific T cell lines (TCL) and clones (TCC) were established from peripheralblood mononuclear cells of allergic patients. Epitope mapping of Api g 1 with overlapping Api g 1-derived peptides revealed one dominant T cell-activating region, Api g 1(109-126). TCL and TCC generated with Api g 1 cross-reacted with the birch pollen allergen and, although initially stimulated with the food allergen, cellular responses to Bet v 1 were stronger than to Api g 1. Epitopemapping with Bet v 1-derived peptides revealed that T cells specific for several distinct epitopes distributed over the complete Bet v 1 molecule could be activated by Api g 1. Bet v 1(109-126) was identified as the most important T cell epitope for cross-reactivity with Api g 1. This epitope shares 72% amino acid sequence similarity with the major T cell-activating region of the food allergen, Api g 1(109-126). Our data provide evidence that humoral as well as cellular reactivity to the major celery allergen is predominantly based on cross-reactivity with the major birch pollen allergen. The activation of Bet v 1-specific Th2 cells by Api g 1, in particular outside the pollen season, may have consequences for birch pollen-allergic individuals.
[26] - Hoffmann-Sommergruber K, Demoly P, Crameri R, Breiteneder H, Ebner C, Laimer Da Camara Machado M, et al. IgE reactivity to Api g 1, a major celery allergen, in a Central European population is based on primary sensitization by Bet v 1. J Allergy Clin Immunol 1999;104:478-484
BACKGROUND: Up to 70% of patients with tree pollen allergy display allergic symptoms when eating certain fruits and vegetables. Homologous proteins with allergenic features are present in a wide range of plant species and can cause allergic reactions. OBJECTIVE: The aim of this study was to evaluate recombinant Api g 1, a major celery allergen, for in vivo and in vitro diagnosis of celery allergy in populations from Davos, Switzerland, and Montpellier, France. METHODS: A group of patients with celery and birch pollen allergy from Davos was tested, and the results from those tests were compared with results from a group of patients allergic to celery from Montpellier. Skin prick tests were performed with a commercial celery extract, crude celery, and purified recombinant Api g 1. Quantitative and qualitative serology was done with natural and recombinant allergens by means of RASTs and immunoblotting. RESULTS: Recombinant Api g 1 allowed accurate in vivo diagnosis of celery allergy in all patients from the Swiss group. RAST results with celery extract were negative in 8 of 24 patients; results of immunoblotting with celery extract were negative in 4 of 24 patients, and results of immunoblotting with recombinant (r)Api g 1 were negative in 8 of 24 patients. In the French group 11 of 12 patients had a positive skin reaction with crude celery extract, but only 2 patients reacted with rApi g 1. RAST results for celery were positive in 8 of 12 patients. In immunoblotting experiments 8 patient sera displayed IgE directed against various celery allergens, whereas no patients sera had rApi g 1-specific IgE. CONCLUSION: Our results document that rApi g 1 allows accurate in vivo diagnosis only in areas where birch trees are common. In areas where no birch trees grow, primary sensitization takes place through different pollen allergens (eg, mugwort pollen). Moreover, it became evident that birch pollen and celery allergy are highly related in Central Europe, whereas in Southern Europe the mugwort-celery type is predominant.
[27] - Jordan-Wagner DL, Whisman BA, Goetz DW. Cross-allergenicity among celery, cucumber, carrot, and watermelon. Ann Allergy 1993;71:70-79
Cross-reactive allergens may be responsible for the clustering of food allergies seen in patients hypersensitive to fruits and vegetables. The pooled sera of six individuals were used to investigate cross-antigenicity among freshly prepared extracts of celery (Cy), cucumber (Cc), carrot (Ct), and watermelon (W). Each patient demonstrated clinical allergy to one or more study foods and, with the exception of Ct in two cases, had IgE to all four extracts by skin test or ELISA. In comparisons of each food against itself and the other three antigens, ELISA inhibition assays demonstrated allergenic similarity among Cy, Cc, Ct, and W by their similar slopes and 50% inhibition concentrations (2.0-7.3 micrograms/mL) In contrast, mountain cedar pollen (MC) produced at 50% inhibition of each food which was 10-fold higher (26.9-70.8 micrograms/mL) and had a flatter slope. Immunoblots of individual sera showed a 15-kD protein band common to all four foods. Pooled sera immunoblot inhibitions (100 and 5 micrograms/mL) demonstrated mutual inhibition of all bands in each of the four foods with the exception of a 28-kD protein of W uniquely inhibited by itself. We conclude that Cy, Cc, Ct, and W possess shared antigens that may account for clustering of these food allergies in patients.
[28] - Vieths S, Jankiewicz A, Wüthrich B, Baltes W. Immunoblot study of IgE binding allergens in celery roots. Ann Allergy Asthma Immunol 1995;75:48-55
The purpose of this study was to characterize the IgE binding components of celery root by immunoblot analysis and to investigate the cross-reactive nature of the allergens. BACKGROUND: Sensitization to celery is very common in patients hypersensitive to mugwort pollen and birch pollen, and is due to cross-reactions of allergen-specific IgE antibodies. Recently, the pan-allergen profilin has been identified as an important cross-reactive allergen in celery, birch pollen and mugwort pollen. Very few data, however, on additional celery allergens are available. METHODS: Sera of 38 patients with an isolated or combined sensitization to birch pollen, mugwort pollen, and celery were investigated by immunoblot and immunoblot inhibition techniques using celery extract and purified Bet v I, the major allergen from birch pollen. The selection of sera was based on serologic sensitization, independent of clinical manifestations. Celery profilin was affinity isolated and analyzed by immunoblotting with patients' sera as well as with rabbit polyclonal antiserum raised against celery profilin. RESULTS: Only weak IgE binding occurred on celery immunoblots in the patient groups with a negative RAST to celery. Sera of 6/8 patients with a birch pollen/celery sensitization recognized a 16-kDa celery allergen that cross-reacted with Bet v I in immunoblot inhibition experiments. In the mugwort pollen/celery and birch pollen/mugwort pollen/celery patient groups, the sera of 6/16 patients contained IgE that bound to a 15 to 16-kDa double band identified as celery profilin. Furthermore, three sera of the birch pollen/mugwort pollen/celery group appeared to contain IgE antibodies against carbohydrate determinants. CONCLUSIONS: The 16-kDa Bet v I-related celery protein appears to be an important allergen for patients sensitized to birch pollen and celery. In contrast IgE binding to celery profilin appears to be more important in patients with an additional sensitization to mugwort pollen.
[30] - Vallier P, Dechamp C, Vial O, Deviller P. A study of allergens in celery with cross-sensitivity to mugwort and birch pollens. Clin Allergy 1988;18:491-500
Sixty-one sera with positive RAST to mugwort pollen (Artemisiae vulgaris) were submitted to RASTs for birch pollen (Betula verrucosa) and celery (Apium graveolens). In 36 cases RAST results were positive for celery. In addition, 23 sera presented specific IgE to birch pollen. The binding of specific IgE to individual allergens in celery, mugwort pollen and birch pollen was studied by the immunoblotting technique. This involved electrophoretic separation of allergenic extracts, electrotransfer of proteins onto nitrocellulose sheets and sensitive immunoenzymatic detection. Eighteen sera had specific IgE binding to two celery components of molecular weight around 15 kD. All these sera also detected a 15 kD allergen in mugwort and two allergens in birch of 14 kD and 16 kD molecular weight. The sera that did not detect the 15 kD bands in celery failed to react with both the 15 kD mugwort component and the 14 and 16 kD birch components. Specific cross-inhibitions of the detection of these allergens on immunoblots were obtained by pre-incubation of the sera with crude extract of the three species. These results strongly suggest that such allergens display some structural identity and that they could be at the origin of some cases of crossed hypersensitivity to celery, mugwort pollen and birch pollen
[32] - Wüthrich B, Stäger J, Johansson SG. Celery allergy associated with birch and mugwort pollinosis. Allergy 1990;45:566-571
Skin prick tests (SPT) with various celery, carrot and potato preparations (raw, cooked, cooking water of each vegetable and allergen extracts) as well as specific IgE determinations by RAST to celery mix, celeriac (or root celery), stick celery and heated celery extracts were performed in 70 patients with positive prick or intracutaneous tests to birch and/or mugwort pollens and celery (extract and/or raw). 94% of the patients showed positive prick tests to raw celeriac, 36% to cooked celeriac and 8/13 to cooking water. Celery-birch positive patients (n = 13) showed negative or low RASTs to heated celery extracts and to stick celery. By contrast, in the celery-mugwort sensitive patients (n = 6) the celery RASTs with heated celery extracts remained clearly positive and high RAST values to stick celery could be found. Celery-birch-mugwort-association (n = 22) favoured more positive results with relatively high values of RAST to celeriac. The results of homologous and heterologous RAST inhibition experiments with birch, mugwort, unheated and heated celery (100 degrees C) carried out in nine celery-RAST positive sera are also discussed.
[33] - Bauer L, Ebner C, Hirschwehr R, Wüthrich B, Pichler C, Fritsch R, et al. IgE cross-reactivity between birch pollen, mugwort pollen and celery is due to at least three distinct cross-reacting allergens: immunoblot investigation of the birch-mugwort-celery syndrome. Clin Exp Allergy 1996;26:1161-1170
Allergy to celery is often associated with sensitization to birch and/or mugwort pollen. OBJECTIVE and METHODS: In a multi-centre study, sera from 23 patients suffering from type 1 allergy to celery and 15 patients with positive celery RAST but no clinical sensitization were compared. To examine whether cross-reactivity between celery and mugwort pollen includes cross-sensitization to birch pollen allergens, we determined cross-reacting structures in birch pollen, mugwort pollen and celery by means of immunoblotting. Inhibition studies were performed by preincubation of sera with extracts of birch pollen, mugwort pollen, and celery. RESULTS: We identified three groups of proteins--homologues of Bet v 1 and birch profilin (Bet v 2) as well as a group of proteins with a molecular range of 46 to 60 kD--displaying IgE-cross-reactivity, which were shared by birch pollen and celery. Two of these groups of allergens (profilin and the 46 to 60 kD proteins) were also present in mugwort pollen. In this paper we demonstrate that most cross-reacting allergens present in mugwort pollen and celery can also be detected in birch pollen extract. CONCLUSION: Therefore we propose, from a serological point of view, to extend the mugwort-celery syndrome to the birch-mugwort-celery syndrome.
[34] - Bauer L, Ebner C, Hirschwehr R, Wüthrich B, Pichler C, Fritsch R, et al. IgE cross-reactivity between birch pollen, mugwort pollen and celery is due to at least three distinct cross-reacting allergens: immunoblot investigation of the birch-mugwort-celery syndrome. Clin Exp Allergy 1996;26:1161-1170
Allergy to celery is often associated with sensitization to birch and/or mugwort pollen. OBJECTIVE and METHODS: In a multi-centre study, sera from 23 patients suffering from type 1 allergy to celery and 15 patients with positive celery RAST but no clinical sensitization were compared. To examine whether cross-reactivity between celery and mugwort pollen includes cross-sensitization to birch pollen allergens, we determined cross-reacting structures in birch pollen, mugwort pollen and celery by means of immunoblotting. Inhibition studies were performed by preincubation of sera with extracts of birch pollen, mugwort pollen, and celery. RESULTS: We identified three groups of proteins--homologues of Bet v 1 and birch profilin (Bet v 2) as well as a group of proteins with a molecular range of 46 to 60 kD--displaying IgE-cross-reactivity, which were shared by birch pollen and celery. Two of these groups of allergens (profilin and the 46 to 60 kD proteins) were also present in mugwort pollen. In this paper we demonstrate that most cross-reacting allergens present in mugwort pollen and celery can also be detected in birch pollen extract. CONCLUSION: Therefore we propose, from a serological point of view, to extend the mugwort-celery syndrome to the birch-mugwort-celery syndrome.
[37] - Wüthrich B, Stäger J, Johansson SG. Celery allergy associated with birch and mugwort pollinosis. Allergy 1990;45:566-571
Skin prick tests (SPT) with various celery, carrot and potato preparations (raw, cooked, cooking water of each vegetable and allergen extracts) as well as specific IgE determinations by RAST to celery mix, celeriac (or root celery), stick celery and heated celery extracts were performed in 70 patients with positive prick or intracutaneous tests to birch and/or mugwort pollens and celery (extract and/or raw). 94% of the patients showed positive prick tests to raw celeriac, 36% to cooked celeriac and 8/13 to cooking water. Celery-birch positive patients (n = 13) showed negative or low RASTs to heated celery extracts and to stick celery. By contrast, in the celery-mugwort sensitive patients (n = 6) the celery RASTs with heated celery extracts remained clearly positive and high RAST values to stick celery could be found. Celery-birch-mugwort-association (n = 22) favoured more positive results with relatively high values of RAST to celeriac. The results of homologous and heterologous RAST inhibition experiments with birch, mugwort, unheated and heated celery (100 degrees C) carried out in nine celery-RAST positive sera are also discussed.
[38] - Ballmer-Weber BK, Hoffmann A, Wüthrich B, Lüttkopf D, Pompei C, Wangorsch A, et al. Influence of food processing on the allergenicity of celery: DBPCFC with celery spice and cooked celery in patients with celery allergy. Allergy 2002;57:228-235
Background:Celery root is often consumed in a processed form as a cooked vegetable or as a spice. So far, however, there has been no information about the allergenicity of processed celery in celery-allergic patients. Methods:In 12 patients with a history of allergic reactions to raw or raw and cooked celery, double-blind placebo-controlled food challenges (DBPCFCs) with raw celery (n=10), cooked celery (110°C/15min; n=11), and celery spice (n=5) were performed. Nine patients underwent an open mucosal challenge with four samples of canned celery retorted at Co-values (cooking effect) of 7.45-76.07 (corresponding to the time periods in minutes at a thermal influence of 100°C). IgE immunoblot analysis of celery extract was performed with sera of all challenged patients. The thermal stability of celery allergen was investigated by enzyme allergosorbent test (EAST) inhibition. Furthermore, intraperitoneal immunization of mice followed by a rat basophil leukemia (RBL) cell mediator release assay was used as a biological in vitro model to assess the allergenicity of processed celery. Results:Six out of 11 patients showed a positive DBPCFC to cooked celery and five out of five patients to celery spice. Allergenicity of celery was preserved in four patients with a positive DBPCFC to cooked celery even if celery was treated at a Co-value of 76.07. Patients with positive DBPCFC to cooked celery reacted to known celery allergens (Apig1, Apig4, cross-reactive carbohydrate determinants CCD). EAST inhibition showed that heat resistance of celery allergens decreases in the following order: CCD>Apig4>Apig1. Accordingly, five of six patients with a positive DBPCFC to cooked celery were sensitized to profilin and/or CCD. The murine model reflected the reactivity of patients sensitized to the major allergen Apig1. Conclusions:1) In a subset of patients with a positive DBPCFC to cooked celery, celery remains allergenic even after extended thermal treatment (76.07 min/100°C). 2) Celery spice is allergenic for patients with an allergy to raw celery. 3) RBL cells sensitized with mouse IgE to raw celery may serve as a useful tool for screening the potential allergenicity of heat-processed products containing celery
[39] - Moneret-Vautrin DA, Morisset M, Lemerdy P, Croizier A, Kanny G. Food allergy and IgE sensitization caused by spices: CICBAA data (based on 589 cases of food allergy). Allerg Immunol (Paris) 2002;34:135-140
BACKGROUND: Spices originate in various botanical families: Apiaceae, Lamiaceae, Lauraceae, Leguminosae, Liliaceae, Myristicaceae, Myrtaceae, Piperaceae, Solanaceae, Zingiberaceae.... METHODOLOGY: Prick-tests to native spices have been carried out in patients suspected of food allergies to spices. The CICBAA data bank includes 589 cases of food allergies, a part of which has benefited from investigations for spices. Data about the rate of sensitization and food allergy are available. RESULTS: Frequent sensitization to Apiaceae is observed: coriander, caraway, fennel, celery: 32% of prick-tests in children, 23% of prick-tests in adults. Sensitization to Liliaceae: garlic, onion, chive, is observed in 4.6% of prick-tests in children, 7.7% of prick-tests in adults. Rare cases of sensitization to paprika and saffron are recorded. Prick-tests to nutmeg, ginger and clove are currently negative. 10 food allergies related to the mugwort-celery-spices syndrome are reported: coriander: 1, caraway: 2, fennel: 3, garlic: 3, onion: 1. Food allergy to spices is unfrequent: 2% of the totality of food allergies. However, only adults are allergic to spices and allergy to spices accounts for 6.4% of food allergies in adults. Tiny amount of proteins are usually ingested. Patients at risk of spice allergy are young adults sensitized to mugwort and birch allergens, sharing cross-sensitization with various food vegetal allergens. The clinical suspicion raises from frequent post-prandial systemic reactions. Other allergens of vegetal origin have to be cleared. Diagnosis can be established by DBPCFC using powdered spices in capsules. [References: 22]
[40] - Wüthrich B. Lethal or life-threatening allergic reactions to food. J Investig Allergol Clin Immunol 2000;10:59-65
Fatal or life-threatening anaphylactic reactions to food occur in infants, children and adults. Atopic individuals with bronchial asthma and prior allergic reactions to the same food are at a particularly high risk, whereby even the mere inhalation of the allergenic food can be fatal. Not only peanuts, seafood and milk can induce severe, potentially lethal anaphylaxis, but indeed a wide spectrum of foods, according to the different patterns of food sensitivity in different countries. Foods with "hidden" allergens and meals at restaurants are particularly dangerous for patients with food allergies. Similarly, schools, public places and restaurants are the major places of risk. However, the main factor contributing to a fatal outcome is the fact that the victims did not carry their emergency kit with adrenaline (epinephrine) with them. In cases of death where food anaphylaxis is suspected, it is important for forensic reasons to preserve uneaten portions of the food in order to identify (hidden) allergens. It is also important to determine postmortem specific serum IgE, tryptase and histamine levels to document the anaphylaxis. There is a need to raise awareness of the diagnosis and treatment of anaphylaxis among doctors, those called upon to administer emergency medical care, and the public, and also to provide increased support for those with potentially fatal food allergies through the help of patients' organizations, and national and international medical societies. The food industry should ensure a policy of comprehensive labelling of ingredients so that even the smallest amount of potentially lethal foodstuffs can be clearly identified. Finally, the pharmaceutical industry should be persuaded to reintroduce an adrenaline inhaler onto the market.
[41] - Ballmer-Weber BK, Vieths S, Lüttkopf D, Heuschmann P, Wüthrich B. Celery allergy confirmed by double-blind, placebo-controlled food challenge: a clinical study in 32 subjects with a history of adverse reactions to celery. J Allergy Clin Immunol 2000;106:373-378
BACKGROUND: Celery root is a frequent cause of food allergy in pollen-sensitized patients. Because of problems in blinding challenges with fresh vegetables and the risk of anaphylactic reactions, no double-blind, placebo-controlled, food challenges (DBPCFCs) with celery have been published so far . OBJECTIVE: The aim of the study was to confirm the clinical relevance of celery as a food allergen by DBPCFCs and to evaluate current diagnostic procedures in patients with true allergy . METHODS: DBPCFCs were performed in 32 patients with a history of an allergic reaction to celery. The patients underwent skin prick tests (SPTs) with celery extracts, crude celery, and different pollen extracts. Specific IgE for celery was determined by using the CAP method . RESULTS: Twenty-two of 32 patients had a positive DBPCFC result. Two patients reacted to placebo, and 8 patients did not respond to the challenge. Of the nonresponders, 4 reacted to an open provocation with celery. The sensitivity of CAP determination for specific IgE (> or =0.7 kU/L) to celery in patients with a positive DBPCFC result was 73%, 48% to 86% for SPTs (> or =3 mm) with commercial extracts, and 96% for prick-to-prick tests with crude celery. The positive predictive value of the SPT and CAP tests was between 87% and 96%, whereas the specificity and negative predictive values were poor . CONCLUSION: This study confirms the importance of celery as a food allergen for use in DBPCFCs. The SPT and CAP methods proved to be reliable for the diagnosis of a relevant allergy to celery in regard to sensitivity and positive predictive value but not to specificity and negative predictive value.
[45] - Pauli G, Bessot JC, Braun PA, Dietemann-Molard A, Kopferschmitt-Kubler MC, Thierry R. Celery allergy: clinical and biological study of 20 cases. Ann Allergy 1988;60:243-246
In 20 patients, the ingestion of celery was responsible for mucocutaneous symptoms (generalized urticaria and angioedema) (18/20) and respiratory disorders (7/20). Four cases of systemic anaphylaxis were observed. The main associated allergic disorder was pollinosis (16/20). Food allergy to other vegetable products, mainly other Umbelliferae and apples, coexisted with celery allergy in 12 cases. It was found that celery allergy is mediated by IgE antibodies: it is easily diagnosed by skin tests (fresh extracts of celery may be used) and by adequate RAST (17 positive results). Cosensitization with mugwort pollen (14 cases) and birch pollen (9 cases) was found. Celery allergens responsible for clinical sensitization originate chiefly in the tuber and are at least partly thermally labile. The frequent association with pollen sensitization suggests the existence of common antigenic epitopes in celery extracts and mugwort and birch pollens. The immunologic investigations carried out so far (RAST inhibition and immunoprint) seem to support this hypothesis.
[46] - Bauer L, Ebner C, Hirschwehr R, Wüthrich B, Pichler C, Fritsch R, et al. IgE cross-reactivity between birch pollen, mugwort pollen and celery is due to at least three distinct cross-reacting allergens: immunoblot investigation of the birch-mugwort-celery syndrome. Clin Exp Allergy 1996;26:1161-1170
Allergy to celery is often associated with sensitization to birch and/or mugwort pollen. OBJECTIVE and METHODS: In a multi-centre study, sera from 23 patients suffering from type 1 allergy to celery and 15 patients with positive celery RAST but no clinical sensitization were compared. To examine whether cross-reactivity between celery and mugwort pollen includes cross-sensitization to birch pollen allergens, we determined cross-reacting structures in birch pollen, mugwort pollen and celery by means of immunoblotting. Inhibition studies were performed by preincubation of sera with extracts of birch pollen, mugwort pollen, and celery. RESULTS: We identified three groups of proteins--homologues of Bet v 1 and birch profilin (Bet v 2) as well as a group of proteins with a molecular range of 46 to 60 kD--displaying IgE-cross-reactivity, which were shared by birch pollen and celery. Two of these groups of allergens (profilin and the 46 to 60 kD proteins) were also present in mugwort pollen. In this paper we demonstrate that most cross-reacting allergens present in mugwort pollen and celery can also be detected in birch pollen extract. CONCLUSION: Therefore we propose, from a serological point of view, to extend the mugwort-celery syndrome to the birch-mugwort-celery syndrome.
[47] - Fötisch K, Altmann F, Haustein D, Vieths S. Involvement of carbohydrate epitopes in the IgE response of celery-allergic patients. Int Arch Allergy Immunol 1999;120:30-42
This study was performed to get further insights into antibody responses to cross-reactive carbohydrate determinants (CCD), including initial experiments to prove the biological activity of anti-CCD IgE. Earlier studies have shown that IgE specific for CCD occurs in about 25% of celery-allergic patients. The clinical significance of these antibody specificities is doubtful. METHODS: Patient sera were selected on the basis of a positive case history of celery allergy and multiple binding to high molecular weight celery allergens on immunoblots. Specific IgE to native and heated celery tuber was determined by the enzyme allergosorbent test (EAST). N-glycans were purified after extensive digestion of specific glycoproteins, such as pineapple stem bromelain, bovine fibrin, and human IgG, and used as antigens in an IgE ELISA as well as in EAST and immunoblotting inhibition experiments. Dose-related histamine release was performed with BSA neoglycoproteins containing 3-4 units of the purified glycopeptides. RESULTS: Seven celery-allergic patients were identified who clearly presented IgE against the N-glycan purified from bromelain which is a common structure within the plant kingdom. Chemical defucosylation showed that alpha1, 3-fucose is a key structure for IgE binding. In patients with anti-CCD IgE, the maximal inhibition of celery EAST by the bromelain glycan ranged from 22 to 100%. Inhibition of celery immunoblots by preincubation of patient serum with this glycan led to a quenching of multiple bands at masses >40 kD. After linking the bromelain glycopeptide to BSA, a strong dose-related histamine release was obtained in a celery-allergic patient, occurring at lower concentrations than with the recombinant major protein allergen from celery, Api g 1. CONCLUSIONS: Our results demonstrate that IgE specific for CCD is common in celery-allergic patients, and can represent the major proportion of IgE against this food. alpha1, 3-fucose was confirmed to be an essential part of the IgE epitope. Immunoblotting inhibition indicated the presence of this carbohydrate determinant on multiple glycoproteins in celery extract. Although histamine release was only performed in 1 patient, our data show that proteins carrying multiple glycan units can be biologically active in patients sensitized to CCD.
[49] - Wüthrich B, Stäger J, Johansson SG. Celery allergy associated with birch and mugwort pollinosis. Allergy 1990;45:566-571
Skin prick tests (SPT) with various celery, carrot and potato preparations (raw, cooked, cooking water of each vegetable and allergen extracts) as well as specific IgE determinations by RAST to celery mix, celeriac (or root celery), stick celery and heated celery extracts were performed in 70 patients with positive prick or intracutaneous tests to birch and/or mugwort pollens and celery (extract and/or raw). 94% of the patients showed positive prick tests to raw celeriac, 36% to cooked celeriac and 8/13 to cooking water. Celery-birch positive patients (n = 13) showed negative or low RASTs to heated celery extracts and to stick celery. By contrast, in the celery-mugwort sensitive patients (n = 6) the celery RASTs with heated celery extracts remained clearly positive and high RAST values to stick celery could be found. Celery-birch-mugwort-association (n = 22) favoured more positive results with relatively high values of RAST to celeriac. The results of homologous and heterologous RAST inhibition experiments with birch, mugwort, unheated and heated celery (100 degrees C) carried out in nine celery-RAST positive sera are also discussed.
[50] - Ballmer-Weber BK, Hoffmann A, Wüthrich B, Lüttkopf D, Pompei C, Wangorsch A, et al. Influence of food processing on the allergenicity of celery: DBPCFC with celery spice and cooked celery in patients with celery allergy. Allergy 2002;57:228-235
Background:Celery root is often consumed in a processed form as a cooked vegetable or as a spice. So far, however, there has been no information about the allergenicity of processed celery in celery-allergic patients. Methods:In 12 patients with a history of allergic reactions to raw or raw and cooked celery, double-blind placebo-controlled food challenges (DBPCFCs) with raw celery (n=10), cooked celery (110°C/15min; n=11), and celery spice (n=5) were performed. Nine patients underwent an open mucosal challenge with four samples of canned celery retorted at Co-values (cooking effect) of 7.45-76.07 (corresponding to the time periods in minutes at a thermal influence of 100°C). IgE immunoblot analysis of celery extract was performed with sera of all challenged patients. The thermal stability of celery allergen was investigated by enzyme allergosorbent test (EAST) inhibition. Furthermore, intraperitoneal immunization of mice followed by a rat basophil leukemia (RBL) cell mediator release assay was used as a biological in vitro model to assess the allergenicity of processed celery. Results:Six out of 11 patients showed a positive DBPCFC to cooked celery and five out of five patients to celery spice. Allergenicity of celery was preserved in four patients with a positive DBPCFC to cooked celery even if celery was treated at a Co-value of 76.07. Patients with positive DBPCFC to cooked celery reacted to known celery allergens (Apig1, Apig4, cross-reactive carbohydrate determinants CCD). EAST inhibition showed that heat resistance of celery allergens decreases in the following order: CCD>Apig4>Apig1. Accordingly, five of six patients with a positive DBPCFC to cooked celery were sensitized to profilin and/or CCD. The murine model reflected the reactivity of patients sensitized to the major allergen Apig1. Conclusions:1) In a subset of patients with a positive DBPCFC to cooked celery, celery remains allergenic even after extended thermal treatment (76.07 min/100°C). 2) Celery spice is allergenic for patients with an allergy to raw celery. 3) RBL cells sensitized with mouse IgE to raw celery may serve as a useful tool for screening the potential allergenicity of heat-processed products containing celery
[51] - Bublin M, Lauer I, Oberhuber C, Alessandri S, Briza P, Radauer C, et al. Production and characterization of an allergen panel for component-resolved diagnosis of celery allergy. Mol Nutr Food Res 2008;52(suppl. 2):S241-S250
In celery a relevant food allergen source, three allergens have been identified so far: Api g 1 and Api g 4, and one glycosylated protein, Api g 5. For component-resolved food allergy diagnosis high amounts of well-defined allergens are needed. Depending on the individual celery allergen, protocols for heterologous production and purification from natural source, respectively, were established to obtain homogenous protein batches. Afterwards the purified recombinant allergens, Api g 1, Api g 4 and natural Api g 5 were characterized regarding their structural integrity and immunological activity. Therefore, several methods were applied. Proteins were identified by partial N-terminal sequencing, protein mass was verified by MS and sequence integrity by MALDI-TOF and N-terminal sequencing after tryptic digestion. Presence of isoforms in natural allergen preparations was identified by 2-DE. Secondary and tertiary structures were evaluated by circular dichroism (CD) spectroscopy and NMR analysis. Finally, IgE binding capacity was verified using selected sera from celery allergic patients in IgE immunoblots and IgE ELISA. These well-defined celery allergens will be used to prove the concept of component-resolved diagnosis and will contribute to improve food allergy diagnosis in the future.
[52] - Wüthrich B, Stäger J, Johansson SG. Celery allergy associated with birch and mugwort pollinosis. Allergy 1990;45:566-571
Skin prick tests (SPT) with various celery, carrot and potato preparations (raw, cooked, cooking water of each vegetable and allergen extracts) as well as specific IgE determinations by RAST to celery mix, celeriac (or root celery), stick celery and heated celery extracts were performed in 70 patients with positive prick or intracutaneous tests to birch and/or mugwort pollens and celery (extract and/or raw). 94% of the patients showed positive prick tests to raw celeriac, 36% to cooked celeriac and 8/13 to cooking water. Celery-birch positive patients (n = 13) showed negative or low RASTs to heated celery extracts and to stick celery. By contrast, in the celery-mugwort sensitive patients (n = 6) the celery RASTs with heated celery extracts remained clearly positive and high RAST values to stick celery could be found. Celery-birch-mugwort-association (n = 22) favoured more positive results with relatively high values of RAST to celeriac. The results of homologous and heterologous RAST inhibition experiments with birch, mugwort, unheated and heated celery (100 degrees C) carried out in nine celery-RAST positive sera are also discussed.
[53] - Jankiewicz A, Baltes W, Bögl KW, Dehne LI, Jamin A, Hoffmann A, et al. Influence of food processing on the immunochemical stability of celery allergens. J Sci Food Agric 1997;75:359-370
Celery roots were processed by microwave heating, cooking, drying, -irradiation, ultra high pressure treatment and high voltage impulse treatment. The immunochemical stabilities of the three known allergenic structures of celery were tested with sera from patients who were sensitised to celery. In addition, rabbit antisera were used to detect the allergens profilin and Api g 1 on celery immunoblots. The specificity and reactivity of IgE from the patients sera were investigated by immunoblotting, by an enzyme allergosorbent test (EAST) and by dose-related IgE inhibition experiments. The results of all three methods agreed closely and indicated high antigenic and allergenic activity in native celery which was reduced by thermal processing. The heat-stability of the known celery allergens decreased in the following order: carbohydrate epitopes> profilin>Api g 1. In contrast, the allergenicity was only mildly reduced by non-thermal processing. The results obtained with human IgE were confirmed by an in vitro mediator-release assay that is based on rat basophil leukemia cells (RBL cells) which were passively sensitised with celery-specific murine IgE. With sera from mice that had been immunised with native celery, the native sample and non-thermal celery preparations elicited the strongest mediator release, whereas a weak response was obtained with samples from heat-processed celery. These results agreed closely with the data obtained in allergic patients whose IgE antibodies were directed against the major protein allergen Api g 1. Our results may be helpful in risk assessment and in selecting food preparations which can be consumed without symptoms by a subgroup of celery-allergic patients with a known sensitisation pattern
[54] - Jankiewicz A, Baltes W, Boegl KW, Dehne LI, Jamin A, Hoffmann A, et al. In vitro study of the gastrointestinal stability of celery allergens. Food Agric Immunol 1998;9:203-217
The gastrointestinal stability of proteins and allergens from native celery roots was studied by a simple two-step in vitro procedure. Commercial enzyme tablets that contained peptic and pancreatic enzymes were used to simulate gastric and duodenal conditions, respectively. The influence on the whole protein pattern was monitored by SDS-PAGE. The antigenicity and allergenicity of the 3 known important allergenic structures of celery were investigated with IgG from 2 rabbit antisera, IgE from sera of allergic patients with known specificity for individual allergens, and by a mediator release assay utilizing allergen-specific polyclonal murine IgE. The following allergens were studied: (i) Api g 1, a 16-kDa celery protein which shares high sequence identity with the major birch pollen allergen, Bet v 1, (ii) celery profilin that belongs to a group of ubiquitous 'plant pan allergens' and (iii) ubiquitous carbohydrate determinants present in many glycans of plant proteins in the mass range of 35-90 kDa. SDS-PAGE indicated degradation of many proteins under gastric conditions, but immunoblotting showed only a weak influence on the antigenicity and IgE reactivity of the allergens. The protein degradation was clearly enhanced after 45 min of pancreatic digestion. To a weaker degree, all allergens were again recognized on immunoblots. The presence of a considerable residual allergenic activity which seems to resist even duodenal conditions was confirmed by the determination of human IgE specific for the digests using an Enzyme Allergosorbent Test. In addition, competitive IgE inhibition assays and measuring the celery-induced mediator release of permanently growing RBL-2H3 cells that had been passively sensitized with celery-specific murine IgE showed similar results. The generation of small IgE binding peptides (<=3 kDa) was tested by ultrafiltration experiments. The whole IgE binding capacity was present in the retentates even after duodenal digestion. It is concluded that, like many other allergens from foods and other sources, the allergens of native celery are relatively stable under gastrointestinal conditions and that residual allergenic activity is due to undigested allergens.
[55] - Vieths S, Lüttkopf D, Reindl J, Anliker MD, Wüthrich B, Ballmer-Weber BK. Allergens in celery and zucchini. Allergy 2002;57(Suppl. 72):100-105
The aim of this study was to confirm allergy to celery tuber and to zucchini, for the first time, by DBPCFC, and to identify the allergens recognized by IgE from DBPCFC-positive patients. Therefore, raw vegetables were hidden in a broccoli drink, and a DBPCFC-procedure was developed that consisted of a spit and swallow protocol, making sure that the procedure was safe for the patients and that reactions strictly localized to the oral cavity as well as systemic reactions could be reproduced by DBPCFC. The allergens in celery and zucchini extract were identified by immunoblot inhibition using allergen extracts, recombinant allergens and purified N-glycans as inhibitors. Celery allergy was confirmed in 69% (22/32) of subjects with a positive case history. Four subjects with a history of allergic reactions to zucchini had a positive DBPCFC to this vegetable. During DBPCFC, systemic reactions were provoked in 50% (11/22) of the patients to celery, and in 3/4 of the zucchini-allergic patients. The Bet v 1-related major celery allergen was detected by IgE of 59% (13/22) of the patients. Cross-reactive carbohydrate epitopes (CCD) bound IgE of 55% (12/22) of the celery-allergic patients and in 2/4 of the subjects with zucchini allergy. Profilin was a food allergen in celery in 23% (5/22) and in zucchini in 2/4 of the cases. A zucchini-specific allergen was detected by IgE from one patient. We conclude that ubiquitous cross-reactive structures are important in allergy to both, celery and zucchini, and that a specific association to birch pollen allergy exists in allergy to celery (mediated by Api g 1), but not in zucchini allergy.
[57] - Fötisch K, Altmann F, Haustein D, Vieths S. Involvement of carbohydrate epitopes in the IgE response of celery-allergic patients. Int Arch Allergy Immunol 1999;120:30-42
This study was performed to get further insights into antibody responses to cross-reactive carbohydrate determinants (CCD), including initial experiments to prove the biological activity of anti-CCD IgE. Earlier studies have shown that IgE specific for CCD occurs in about 25% of celery-allergic patients. The clinical significance of these antibody specificities is doubtful. METHODS: Patient sera were selected on the basis of a positive case history of celery allergy and multiple binding to high molecular weight celery allergens on immunoblots. Specific IgE to native and heated celery tuber was determined by the enzyme allergosorbent test (EAST). N-glycans were purified after extensive digestion of specific glycoproteins, such as pineapple stem bromelain, bovine fibrin, and human IgG, and used as antigens in an IgE ELISA as well as in EAST and immunoblotting inhibition experiments. Dose-related histamine release was performed with BSA neoglycoproteins containing 3-4 units of the purified glycopeptides. RESULTS: Seven celery-allergic patients were identified who clearly presented IgE against the N-glycan purified from bromelain which is a common structure within the plant kingdom. Chemical defucosylation showed that alpha1, 3-fucose is a key structure for IgE binding. In patients with anti-CCD IgE, the maximal inhibition of celery EAST by the bromelain glycan ranged from 22 to 100%. Inhibition of celery immunoblots by preincubation of patient serum with this glycan led to a quenching of multiple bands at masses >40 kD. After linking the bromelain glycopeptide to BSA, a strong dose-related histamine release was obtained in a celery-allergic patient, occurring at lower concentrations than with the recombinant major protein allergen from celery, Api g 1. CONCLUSIONS: Our results demonstrate that IgE specific for CCD is common in celery-allergic patients, and can represent the major proportion of IgE against this food. alpha1, 3-fucose was confirmed to be an essential part of the IgE epitope. Immunoblotting inhibition indicated the presence of this carbohydrate determinant on multiple glycoproteins in celery extract. Although histamine release was only performed in 1 patient, our data show that proteins carrying multiple glycan units can be biologically active in patients sensitized to CCD.
[58] - Lüttkopf D, Ballmer-Weber BK, Wüthrich B, Vieths S. Celery allergens in patients with positive double-blind placebo-controlled challenge. J Allergy Clin Immunol 2000;106:390-399
BACKGROUND: Recently, for the first time, allergy to celery was confirmed by double-blind placebo-controlled food challenge (DBPCFC). Api g 1, Api g 4, cross-reactive carbohydrate determinants (CCD), and a 60 kDa allergen have been described as celery allergens . OBJECTIVE: To get insights in IgE responses of patients with a positive DBPCFC to celery tuber (celeriac) compared with patients with a negative challenge test . METHODS: Specific IgE to native and heated celery tuber and to recombinant Api g 1, the major celery allergen, were determined by enzyme allergosorbent test and immunoblotting. IgE binding to Api g 1, Api g 4, and CCD was confirmed by inhibition experiments that used recombinant Api g 1, recombinant Api g 4, pure N-glycans, and extracts of celeriac, lychee fruit, and pollens of birch, mugwort, and timothy grass as inhibitors . RESULTS: Immunoblotting with sera from 22 patients with a positive DBPCFC to celeriac confirmed the presence of known allergenic structures: The major allergen Api g 1 (16 kDa) was recognized by IgE from 13 of 22 patients (59%). Another major allergen was CCD, determined by IgE reactivity in 12 of 22 patients (55%). Celery profilin, Api g 4, was recognized by IgE from 5 of 22 patients (23%) . CONCLUSION: Our DBPCFC-positive patients exclusively presented IgE to known celery allergens, although the prevalences were slightly different than were previously reported. No obvious differences were found in patients with positive IgE antibody but negative challenge test. IgE binding to all 3 structures in celeriac extract was inhibited by birch pollen extract, whereas mugwort pollen extract could only inhibit IgE reactivity to Api g 4 and CCD. Inhibition experiments with a purified carbohydrate moiety clearly showed that the IgE epitope mannose-xylose-fucose-glycan (Manalpha1-6[Xylbeta1-2]Manbeta1-4GlcNAcbeta1-4[ Fucalpha1-3]GlcNAc) or a closely related structure is present in celeriac extract and is important in patients with clinical allergy to celery.
[59] - Bublin M, Radauer C, Wilson IB, Kraft D, Scheiner O, Breiteneder H, et al. Cross-reactive N-glycans of Api g 5, a high molecular weight glycoprotein allergen from celery, are required for immunoglobulin E binding and activation of effector cells from allergic patients. FASEB J 2003;17:1697-1699
Allergy diagnosis relying on the determination of specific IgE is frequently complicated by the presence of cross-reacting IgE of unclear clinical relevance. Particularly, the anaphylactogenic activity of IgE directed to cross-reactive carbohydrate moieties of glycoproteins from plants and invertebrates has been a matter of debate. In this study, we present the biochemical and immunological characterization of Api g 5, a glycoprotein allergen from celery with homology to FAD containing oxidases. Carbohydrate analysis of the allergen revealed the presence of glycans carrying fucosyl and xylosyl residues, structures previously shown to bind IgE. Chemical deglycosylation of the protein completely abolished binding of serum IgE from all 14 patients tested. Likewise, basophils from a patient allergic to mugwort pollen and celery were stimulated only by native Api g 5, whereas the deglycosylated allergen did not trigger release of histamine. IgE inhibition immunoblots showed that native Api g 5 other than the deglycosylated protein completely inhibited IgE binding to high molecular weight allergens in protein extracts from birch pollen, mugwort pollen, and celery. A similar inhibition was accomplished using the IgE binding oligosaccharide, MUXF, coupled to bovine serum albumin. All these observations taken together confer convincing evidence that IgE directed to cross-reactive carbohydrates is capable of eliciting allergic reactions in vivo.
[60] - van Ree R. Carbohydrate Epitopes and Their Relevance for the Diagnosis and Treatment of Allergic Diseases. Int Arch Allergy Immunol 2002;129:189-197
Allergenicity of plant and invertebrate N-glycans has been shown to be caused by the presence of two typical nonmammalian substitutions: an (1,3)-fucose linked to the proximal N-acetylglucosamine and a (1,2)-xylose linked to the core mannose. IgE antibodies against these carbohydrate structures are induced upon exposure to pollen or after insect stings, and result in extensive cross-reactivity to plant and invertebrate foods. These cross-reactive IgE antibodies have been shown to possess variable degrees of biological activity, but have never been convincingly shown to induce clinical food allergy. The most likely explanation for this lack of clinical relevance has to be sought in a combination of epitope valency and antibody affinity. In diagnostic tests, these antibodies are at the basis of many false-positive test results for food allergy. Recombinant technologies offer the possibility to produce allergens that do not carry IgE-binding glycans. Whether their absence or presence is of importance for the application of recombinant allergens in immunotherapy is still largely unknown.
[61] - Bauermeister K, Ballmer-Weber BK, Bublin M, Fritsche P, Hanschmann KM, Hoffmann-Sommergruber K et al. Assessment of component-resolved in vitro diagnosis of celeriac allergy. J Allergy Clin Immunol 2009;124:1273-1281
BACKGROUND: Previous studies have demonstrated insufficient sensitivity of commercially available celeriac extract reagents in the diagnosis of celeriac allergy. OBJECTIVE: We sought to assess the diagnostic performance of specific IgE determination based on recombinant and purified natural celeriac allergens in comparison with an extract-based assay and to investigate interference by IgE to cross-reactive carbohydrate determinants and its biologic activity. METHODS: Twenty-four subjects with a positive double-blind, placebo-controlled food challenge result to celeriac; 20 atopic control subjects with birch pollen allergy who tolerated celeriac; and 20 nonatopic subjects were enrolled. IgE binding was investigated for celeriac allergens (rApi g 1.01, rApi g 4, and nApi g 5), extract reagents (celeriac, birch, mugwort, and timothy grass pollen), birch pollen allergens (rBet v 1 and rBet v 2), and cross-reactive carbohydrate determinants by means of ImmunoCAP analysis. Biologic activity of allergens was determined based on basophil mediator release. RESULTS: Component-resolved ImmunoCAP analysis considerably increased the sensitivity to detect celeriac-specific IgE by 20%. Sensitization to carbohydrate structures was detected in 38% of patients with celeriac allergy, and there was an excellent correlation between sensitization to the glycoprotein Api g 5 and isolated glycan. Positive results among atopic control subjects were mainly caused by protein allergens, whereas the effect of carbohydrate epitopes was marginal. The ability of allergens to induce mediator release decreased in the order Bet v 1 > Api g 1 > Api g 5, confirming the low biologic activity of IgE to carbohydrate epitopes. CONCLUSION: Component-resolved diagnosis allowed an increase in diagnostic sensitivity from 67% to 88% compared with extract-based diagnosis. Sensitization to Api g 5 was attributable to its glycan moieties but did not interfere with diagnostic specificity.
[62] - 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.
[63] - Erdmann SM, Sachs B, Schmidt A, Merk HF, Scheiner O, Moll-Slodowy S, et al. In vitro Analysis of Birch-Pollen-Associated Food Allergy by Use of Recombinant Allergens in the Basophil Activation Test. Int Arch Allergy Immunol 2005;136:230-238
BACKGROUND: Basophil activation is associated with the expression of CD63. In birch-pollen-associated food allergy to celery, carrot and apple, Bet v 1, Api g 1, Dau c 1 and Mal d 1 are major allergens. Recombinant allergens have not yet been used in the CD63-based basophil activation test (BAT) . OBJECTIVE: To evaluate the feasibility of using recombinant allergens in the BAT in the diagnosis of allergy to apple, carrot and celery and to compare results with routine tests, i.e. skin prick tests (SPTs) and specific IgE . METHODS: Thirty-two patients with an oral allergy syndrome induced by apple, carrot or celery and 22 controls were studied. SPTs were performed with native foods. Specific IgE was determined by the CAP method and basophil activation by flowcytometry upon double staining with anti-IgE/anti-CD63 monoclonal antibodies after incubating with purified recombinant Bet v 1, Bet v 2, Api g 1, Dau c 1 and Mal d 1 . RESULTS: By the combined use of the BAT and the CAP method, sensitization to Bet v 1 and Bet v 2 was detected in 100 and 25% of all subjects, respectively. Sensitivity of specific IgE for apple, carrot and celery was 60, 70 and 75% with corresponding specificities of 64, 86 and 82%. Sensitivity of the BAT for Mal d 1, Dau c 1 and Api g 1 was 75, 65 and 75% with corresponding specificities of 68, 100 and 77% . CONCLUSIONS: The BAT using recombinant allergens provides a valuable new in vitro method for the detection of sensitization to foods. Although double-blind placebo-controlled food challenges remain the gold standard to confirm food allergy, the CD63-based BAT with recombinant allergens may supplement routine tests for allergy diagnosis.
[64] - Ballmer-Weber BK, Weber JM, Vieths S, Wüthrich B. Predictive value of the sulfidoleukotriene release assay in oral allergy syndrome to celery, hazelnut, and carrot. J Investig Allergol Clin Immunol 2008;18:93-99
BACKGROUND: Patients sensitized to birch pollen frequently suffer from a food allergy to plant foods such as celery, carrots, or hazelnut. One of the main manifestations of birch pollen-related food allergy is the oral allergy syndrome. Skin tests and allergen-specific immunoglobulin (Ig) E determinations are poor predictors of such reactions when assessed by double-blind placebo-controlled food challenge (DBPCFC). OBJECTIVE: To investigate whether a cellular test based on leukotriene release from basophils, the cellular antigen stimulation test in combination with enzyme-linked immunosorbent assay (CAST-ELISA), is predictive of pollen-related food allergy. METHODS: Birch pollen-sensitized patients with positive DBPCFC to celery (n=21), hazelnut (n=15), and carrot (n=7) underwent skin tests along with determination of specific IgE and CAST-ELISA for the respective allergens. The results were compared with those of 24 birch pollen-sensitized patients with negative open food challenge to celery, hazelnut, and carrot. RESULTS: While skin prick tests had a sensitivity of 85%, 80%, and 29% for commercial extracts of celery, hazelnut, and carrot, respectively, prick testing with self-prepared extracts yielded sensitivities of 100%, 80%, and 100%, respectively. For specific IgE determinations, sensitivities were 71%, 73%, and 57%, respectively, and the respective specificities were 67%, 73%, and 60%. For CAST-ELISA with various sources and doses of allergens, the sensitivity varied from 71% to 95% for celery, 73% to 80% for hazelnut, and 43% to 86% for carrot. The respective specificities were 67% to 92%, 75% to 88%, and 77% to 91%. Analysis of the predictive value of CAST-ELISA with receiver operating characteristic curves showed that the results of the tests were more predictive of pollen-related food allergy than quantitative allergen-specific IgE determinations. CONCLUSIONS: CAST-ELISA is more specific than routine diagnostic tests for the diagnosis of pollen-related food allergy to celery, hazelnut, and carrot.
[65] - Pauli G, Oster JP, Deviller P, Heiss S, Bessot JC, Susani M, et al. Skin testing with recombinant allergens rBet v 1 and birch profilin, rBet v 2: diagnostic value for birch pollen and associated allergies. J Allergy Clin Immunol 1996;97:1100-1109
This study assesses the value of two recombinant birch allergens for diagnosis of patients sensitized to birch pollen with or without associated food allergy. METHODS: Fifty-one patients with positive skin test responses to Betulaceae and seven nonallergic control subjects were investigated; specific IgE antibodies were evaluated by specific immunoassay and blot immunodetection. RESULTS: Among 51 patients, 47 reacted to rBet v 1 and 10 to rBet v 2. Seven patients reacted to both recombinant allergens. In skin prick tests we found a correlation between the wheal produced by the commercial birch extract and the wheal produced by rBet v 1. Among 47 patients with positive test responses to rBet v 1, 83% had IgE binding to the Bet v 1 protein as determined by immunoblotting. Among 10 patients sensitized to rBet v 2, six had IgE binding to Bet v 2. Eleven patients with negative results, as determined by immunoblotting, had low levels of birch IgE in the sera (less than 10 kU/L) and low concentrations of IgE to rBet v 1 or rBet v 2 in ELISA. The nonallergic control subjects (n = 7) did not react to rBet v 1 or rBet v 2 in skin prick tests, nor did they have detectable amounts of specific IgE to rBet v 1 or rBet v 2. Histamine release tests confirmed sensitization to Bet v 1 in two patients with discordant results; for Bet v 2, one patient had positive results only at a high concentration, and one had results that remained negative. Thirty-four patients had birch pollinosis, and all reacted to rBet v 1. Patients who were monosensitized to birch never reacted to rBet v 2. Sensitization to rBet v 2 was only found in patients who reacted to other pollens (mainly grass). Twenty-nine patients demonstrated allergy to apples, cherries, or hazelnuts; and all reacted to rBet v 1. Among 11 patients with allergy to Umbelliferae, only three reacted to rBet v 2. CONCLUSIONS: Use of the two recombinant allergens (rBet v 1 and rBet v 2) always permits the diagnosis of birch sensitization. Sensitization to rBet v 1 is specific for birch and Rosaceae allergies, whereas sensitization to birch profilin, Bet v 2, is encountered in multisensitized subjects and is not always related to Umbelliferae allergy.
[66] - Bublin M, Lauer I, Oberhuber C, Alessandri S, Briza P, Radauer C, et al. Production and characterization of an allergen panel for component-resolved diagnosis of celery allergy. Mol Nutr Food Res 2008;52(suppl. 2):S241-S250
In celery a relevant food allergen source, three allergens have been identified so far: Api g 1 and Api g 4, and one glycosylated protein, Api g 5. For component-resolved food allergy diagnosis high amounts of well-defined allergens are needed. Depending on the individual celery allergen, protocols for heterologous production and purification from natural source, respectively, were established to obtain homogenous protein batches. Afterwards the purified recombinant allergens, Api g 1, Api g 4 and natural Api g 5 were characterized regarding their structural integrity and immunological activity. Therefore, several methods were applied. Proteins were identified by partial N-terminal sequencing, protein mass was verified by MS and sequence integrity by MALDI-TOF and N-terminal sequencing after tryptic digestion. Presence of isoforms in natural allergen preparations was identified by 2-DE. Secondary and tertiary structures were evaluated by circular dichroism (CD) spectroscopy and NMR analysis. Finally, IgE binding capacity was verified using selected sera from celery allergic patients in IgE immunoblots and IgE ELISA. These well-defined celery allergens will be used to prove the concept of component-resolved diagnosis and will contribute to improve food allergy diagnosis in the future.
[67] - Bauermeister K, Ballmer-Weber BK, Bublin M, Fritsche P, Hanschmann KM, Hoffmann-Sommergruber K et al. Assessment of component-resolved in vitro diagnosis of celeriac allergy. J Allergy Clin Immunol 2009;124:1273-1281
BACKGROUND: Previous studies have demonstrated insufficient sensitivity of commercially available celeriac extract reagents in the diagnosis of celeriac allergy. OBJECTIVE: We sought to assess the diagnostic performance of specific IgE determination based on recombinant and purified natural celeriac allergens in comparison with an extract-based assay and to investigate interference by IgE to cross-reactive carbohydrate determinants and its biologic activity. METHODS: Twenty-four subjects with a positive double-blind, placebo-controlled food challenge result to celeriac; 20 atopic control subjects with birch pollen allergy who tolerated celeriac; and 20 nonatopic subjects were enrolled. IgE binding was investigated for celeriac allergens (rApi g 1.01, rApi g 4, and nApi g 5), extract reagents (celeriac, birch, mugwort, and timothy grass pollen), birch pollen allergens (rBet v 1 and rBet v 2), and cross-reactive carbohydrate determinants by means of ImmunoCAP analysis. Biologic activity of allergens was determined based on basophil mediator release. RESULTS: Component-resolved ImmunoCAP analysis considerably increased the sensitivity to detect celeriac-specific IgE by 20%. Sensitization to carbohydrate structures was detected in 38% of patients with celeriac allergy, and there was an excellent correlation between sensitization to the glycoprotein Api g 5 and isolated glycan. Positive results among atopic control subjects were mainly caused by protein allergens, whereas the effect of carbohydrate epitopes was marginal. The ability of allergens to induce mediator release decreased in the order Bet v 1 > Api g 1 > Api g 5, confirming the low biologic activity of IgE to carbohydrate epitopes. CONCLUSION: Component-resolved diagnosis allowed an increase in diagnostic sensitivity from 67% to 88% compared with extract-based diagnosis. Sensitization to Api g 5 was attributable to its glycan moieties but did not interfere with diagnostic specificity.
[68] - Erdmann SM, Sachs B, Schmidt A, Merk HF, Scheiner O, Moll-Slodowy S, et al. In vitro Analysis of Birch-Pollen-Associated Food Allergy by Use of Recombinant Allergens in the Basophil Activation Test. Int Arch Allergy Immunol 2005;136:230-238
BACKGROUND: Basophil activation is associated with the expression of CD63. In birch-pollen-associated food allergy to celery, carrot and apple, Bet v 1, Api g 1, Dau c 1 and Mal d 1 are major allergens. Recombinant allergens have not yet been used in the CD63-based basophil activation test (BAT) . OBJECTIVE: To evaluate the feasibility of using recombinant allergens in the BAT in the diagnosis of allergy to apple, carrot and celery and to compare results with routine tests, i.e. skin prick tests (SPTs) and specific IgE . METHODS: Thirty-two patients with an oral allergy syndrome induced by apple, carrot or celery and 22 controls were studied. SPTs were performed with native foods. Specific IgE was determined by the CAP method and basophil activation by flowcytometry upon double staining with anti-IgE/anti-CD63 monoclonal antibodies after incubating with purified recombinant Bet v 1, Bet v 2, Api g 1, Dau c 1 and Mal d 1 . RESULTS: By the combined use of the BAT and the CAP method, sensitization to Bet v 1 and Bet v 2 was detected in 100 and 25% of all subjects, respectively. Sensitivity of specific IgE for apple, carrot and celery was 60, 70 and 75% with corresponding specificities of 64, 86 and 82%. Sensitivity of the BAT for Mal d 1, Dau c 1 and Api g 1 was 75, 65 and 75% with corresponding specificities of 68, 100 and 77% . CONCLUSIONS: The BAT using recombinant allergens provides a valuable new in vitro method for the detection of sensitization to foods. Although double-blind placebo-controlled food challenges remain the gold standard to confirm food allergy, the CD63-based BAT with recombinant allergens may supplement routine tests for allergy diagnosis.
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