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Les Fagales
lundi 8 février 2010, par
Les arbres appartenant à l’ordre des Fagales ont en commun de posséder des pollens fréquemment allergisants.
Cette propriété commune provient d’une famille d’allergènes qui semble caractéristique des pollens de Fagales, les protéines PR-10 ou Bet v 1-like (= homologues de l’allergène Bet v 1 du bouleau).
Parmi les Fagales on distingue notamment deux familles botaniques : les Bétulacées et les Fagacées.
- Cette dernière comprend les chênes, les hêtres et les châtaigniers.
- Les Bétulacées sont divisées en Bétuloidées, avec le bouleau et l’aulne, et en Coryloïdées, avec le noisetier, le charme et le charme-houblon.
Le pollen de bouleau est le mieux connu sur le plan épidémiologique et moléculaire.
Mais des allergènes homologues à ceux du bouleau ont été caractérisés ou suggérés (réactions croisées) dans les autres pollens de Fagales.
Le tableau ci-après donne l’état des lieux pour les allergènes PR-10, les profilines et les polcalcines.
| PR 10 (Bet v 1 like) | Profilines | Polcalcines (CaBP 2EF-hand) | ||
|---|---|---|---|---|
| Bouleau | Bet v | 1 | 2 | 4 |
| Aulne | Aln g | 1 | 2 | 4 |
| Noisetier | Cor a | 1.01 | 2 | |
| Charme | Car b | 1 | 2 | X |
| Châtaignier | Cas s | 1 | X | |
| Hêtre | Fag s | 1 | 2 | 4 |
| Chêne | Que a | 1 | X | X |
x = allergène présent mais pas de dénomination de type IUIS pour le moment
Les réactions croisées entre allergènes homologues de Fagales sont extensives 
. Elles ont principalement été vérifiées pour les PR-10.
On conçoit donc aisément qu’un patient pollinique au bouleau puisse présenter des tests positifs (TC, in vitro) pour l’aulne ou le noisetier.
Mais le contraire est vu également : ainsi dans une étude menée dans la région de Rome, dépourvue de bouleaux, tous les patients positifs en TC pour le bouleau étaient positifs pour le chêne et le noisetier .
D’ailleurs des mélanges "bétulacées" ou "fagales" sont parfois employés en partant du principe que la réactivité pour un tel groupe de pollens vaut notamment pour le bouleau.
In vitro, de très fortes corrélations sont vues entre bouleau et aulne (r = 0,97), mais également antre aulne et hêtre (r = 0,88) ou aulne et chêne (r = 0,90) dans les contrées où l’aulne est la principale Bétulacée .
Ailleurs, il a été montré que c’est Bet v 1 qui initie la réactivité à Aln g 1 (aulne) et à Cor a 1 (noisetier) .
La pollinose au bouleau peut-elle générer une pollinose à d’autres Fagales ?
- Quand les saisons polliniques sont bien séparées, un tel effet peut être visible. Cela est évoqué pour le chêne notamment .
- Quand les pollinisations sont synchrones, il n’est pas facile de distinguer les réactivités croisées des véritables sensibilisations. C’est le cas pour le charme-houblon (Ostrya carpinifolia) où pratiquement tous les patients positifs pour ce pollen sont positifs pour le bouleau.
Les pollens de Fagales s’inscrivent-ils dans un syndrome Fagales-aliments ?
Il est possible que dans des environnements où d’autres Fagales que le bouleau sont prévalentes on puisse observer une allergie alimentaire induite par la sensibilisation à des PR-10 autres que Bet v 1. C’est le cas au Japon pour l’aulne .
Pollen de charme
La situation est peut-être un peu différente avec le pollen de charme (Carpinus betulus) dans des régions où cet arbre est bien représenté.
- En Suisse une étude montrait 13 % de sujets réagissant au charme mais pas au bouleau .
- En Slovénie, un léger excédent de réactivité croisée était noté en faveur du charme comparativement au bouleau .
- La capacité immunogène de l’allergène PR-10 du charme, Car b 1, a été testée vis à vis de clones T Bet v 1-spécifiques : elle s’avère meilleure que celle de Cor a 1 (noisetier) ou d’Aln g 1 (aulne) et surtout que celle de Que a 1 (chêne) .
Cette gradation parmi les pollens de Fagales se retrouve plus ou moins dans l’incidence des pollinoses à tel ou tel pollen et dans les réactivités en TC ou in vitro.
Il pourrait être utile de tester Car b 1 plutôt que Bet v 1 dans un contexte d’exposition majoritaire au pollen de charme .
Pollen de chêne :
En Suède, tous les sujets Que a 1 positifs sont Bet v 1 positifs
Dans la région romaine, dépourvue de bouleaux, tous les TC positifs pour le chêne sont positifs pour le noisetier et la fréquence des TC positifs pour différentes Fagales est très supérieure en cas de chêne positif, comme le montre le tableau suivant :
| % de TC positifs pour | en cas de TC positif pour | ||
|---|---|---|---|
| noisetier | noisetier et bouleau | noisetier et bouleau et chêne | |
| Aulne | 0 | 16 | 56 |
| Charme | 25 | 19 | 58 |
| Hêtre | 0 | 6 | 55 |
| Châtaignier | 0 | 4 | 29 |
La positivité pour le chêne ne traduit pas une sensibilisation particulière au chêne mais plutôt une sensibilité plus grande vis à vis des allergènes PR-10.
Cela a été observé ailleurs, les tests pour Bet v 1 étant plus souvent positifs chez les sujets positifs en TC pour un mélange de Fagacées .
De même, la mono-réactivité aux Fagacées était très rare dans une étude en Grande-Bretagne .
Malgré tout, il est possible que tester rQue a 1 plutôt que rBet v 1 soit plus pertinent dans un environnement dépourvu de bouleaux car Que a 1 n’a que 58% d’identité avec Bet v 1 .
Pollen de noisetier
Quel impact pour le pollen de noisetier ?
En dehors d’une pollinose clairement distincte temporellement avec le bouleau, le noisetier peut-il favoriser ou générer une pollinose à d’autres Fagales, à l’image de la pollinose au bouleau ?
Dans les régions où bouleau et noisetiers sont présents tous les deux, il est habituel d’observer des réponses in vitro supérieures pour le bouleau et des réactions croisées plutôt en faveur du bouleau.
Van Ree donne un rapport noisetier/bouleau in vitro de 0,53 contre 1,02 pour aulne/bouleau, l’aulne étant botaniquement plus proche du bouleau que n’est le noisetier .
Mais ces résultats in vitro sont insuffisants pour en déduire un effet in vivo.
Sans être spécifiquement démontré, on peut s’attendre, néanmoins, à ce qu’une sensibilisation au noisetier joue un rôle de "starter" pour le bouleau qui est proche immunologiquement et qui le suit dans l’ordre des émissions polliniques.
Une autre question serait : quel risque de développer une pollinose au bouleau ont des patients qui se sont sensibilisés au noisetier dans leur pays d’origine ?
- Cela n’est pas négligeable quand des taux de 80 % de TC positifs noisetier en Espagne ou de 13% de TC positifs uniquement pour le noisetier à Rome sont relevés hors de tout contact avec des bouleaux.
- Même si une partie de cette réactivité cutanée est à attribuer aux profilines et/ou polcalcines dans les cas de poly-pollinose, une réactivité pour Bet v 1 (c’est-à-dire en fait pour Cor a 1 du noisetier) est présente chez de nombreux patients .
- Un patient ayant cette sensibilisation vis à vis de Cor a 1 semble donc prédisposé à développer une réactivité au bouleau s’il vient à être en contact avec ce pollen.
Pollen de châtaignier
La situation du pollen de châtaignier au sein des Fagales a été moins bien étudiée.
Le pollen de châtaignier a le désavantage d’être émis a une période où les graminées ont le devant de la scène.
Ce pollen semble, malgré tout, avoir une allergénicité modeste car dans des régions où il est fortement présent la prévalence d’une positivité en TC reste faible (7-8 %) .
Ailleurs, la réactivité croisée entre la PR-10 du châtaignier (Cas s 1) et Bet v 1 est très en faveur de Bet v 1 , montrant Cas s 1 plutôt comme un épiphénomène d’une sensibilisation au bouleau.
Pollen de hêtre
On possède peu de données concernant le pollen de hêtre sur le plan clinique.
Si des différences de contenus en protéines sont vues entre hêtre et bouleau en SDS-PAGE, les réactivité croisées entre ces deux pollens s’étendent des PR-10 aux profilines et aux polcalcines . Il est donc bien difficile de distinguer une sensibilisation au pollen de hêtre qui soit indépendante d’une sensibilisation à une autre Fagale.
[1] - Niederberger V, Pauli G, Grönlund H, Fröschl R, Rumpold H, Kraft D, et al. Recombinant birch pollen allergens (rBet v1 and rBet v2) contain most of the IgE epitopes present in birch, alder, hornbeam, hazel, and oak pollen: a quantitative IgE inhibition study with sera from different populations. J Allergy Clin Immunol 1998;102:579-591
BACKGROUND: Pollen from trees of the order Fagales are important allergen sources in most parts of the world. Clinical, immunochemical, and molecular biology studies indicate that they contain cross-reactive allergens. The major birch pollen allergen, Bet v 1, and birch profilin, Bet v 2, a highly cross-reactive allergen, have been cloned and expressed in Escherichia coli. OBJECTIVE: The purpose of this study was to demonstrate the presence of allergens in Fagales pollens that share IgE epitopes with recombinant Bet v 1 and Bet v 2 and to determine the percentage of birch, alder, hornbeam, hazel, and oak pollen-specific IgE that can be preabsorbed with rBet v 1 and rBet v 2 from 102 sera of different populations of subjects allergic to Fagales tree pollen.
METHODS: The presence of rBet v 1- and rBet v 2-homologous allergens in tree pollen extracts was investigated by IgE immunoblot inhibition experiments, and the percentage of tree (birch, alder, hornbeam, hazel, and oak) pollen-specific IgE that was bound by a mixture of rBet v 1 and rBet v 2 was determined by RAST-based quantitative IgE inhibition experiments. The clinical significance of IgE antibody cross-reactivity was studied by skin prick testing with rBet v 1, rBet v 2, and Fagales pollen extracts.
RESULTS: Natural birch, alder, hornbeam, hazel, and oak pollen contain allergens that share IgE epitopes with rBet v 1 and rBet v 2. A combination of rBet v 1 and rBet v 2 accounted for 82% of tree pollen-specific IgE on average. Most of the tree pollen-specific IgE was directed against rBet v 1. CONCLUSION: rBet v 1 and rBet v 2 contain most of the Fagales pollen-specific IgE epitopes and may therefore substitute natural tree pollen extracts not only for diagnosis but also for patient-tailored immunotherapy of tree pollen allergy.
↩[2] - Mari A. Multiple pollen sensitization: a molecular approach to the diagnosis. Int Arch Allergy Immunol 2001;125:57-65
BACKGROUND: Sensitization to multiple pollen species is a frequent diagnostic event. Several allergenic molecules with a high level of homology have been identified in divergent pollen families and named panallergens.
METHODS: We sought to define the criteria to evaluate the prevalence of the multiple pollen sensitization, to identify specific markers of this condition, and to correlate them with the underlying allergic disease. Patients presenting an allergic respiratory disease underwent skin testing with 23 pollens. Patients fulfilling predefined selection criteria were grouped and classified as having multiple pollen sensitization. Patients in each subgroup were tested for IgE to rBet v 2, rJun o 2, rBet v 1, rPhl p 5 and bromelain. Demographical, allergological and clinical data were recorded in the subgroup of patients with multiple pollen sensitization.
RESULTS: Seventeen percent of the pollen-sensitized patients formed the multiple pollen-sensitized subgroup. These subjects were positive for most of the pollen species tested regardless of known exposure to them. None of the subjects sensitized to less than six pollen species were positive to panallergens, whereas 55% of the sera of the multiple pollen-sensitized group were positive to rBet v 2, and 15% to rJun o 2. IgE to rBet v 1 and rPhl p 5 were found positive in all the subgroups. Age, gender, bronchial asthma, oral allergy syndrome, skin test reactivity and previous specific immunotherapy differed significantly when these two subsets were considered.
CONCLUSIONS: Allergy diagnosis based on allergenic molecules is crucial in the patient with multiple pollen sensitization. This condition appears to be determined by the sensitization to defined allergenic components (panallergens) rather than by pollen of multiple species as such. Detection of IgE to nonpanallergenic molecules allows to identify more relevant allergenic sources. Clinical aspects of the underlying allergic disease (e.g. asthma and oral allergy syndrome) seem to be differently related to IgE reactivity to panallergens
↩[3] - Maeda Y, Ono E, Fukutomi Y, Taniguchi M, Akiyama K. Correlations Between Alder Specific IgE and Alder-related Tree Pollen Specific IgE by RAST Method. Allergol Int 2008;57:79-81
Background: Wild birch trees grow in limited areas in Japan and are not a common aero-allergen. However, many patients who do not live in the area show positive birch pollen Radioallergosorbent Test (RAST). Therefore, being sensitized by another tree pollen which is closely related to birch may result in showing a specific IgE antibody to birch. Alder is a one of these trees and in the past it grew widely in Japan. However, there is no available RAST data as to the correlations between alder and alder-related trees.
Methods: We measured the alder specific IgE (CAP-RAST, Phadea) in stored sera which was positive in birch RAST (228 samples), beech RAST (36 samples), oak RAST (152 samples) and cedar RAST (411 samples) and examined correlations between the RAST of alder and other trees.
Results: The correlation coefficient value of birch was very high (0.971). The other coefficient values of beech and oak were high (0.884 in beech and 0.895 in oak) but were slightly lower than that of the birch. This means that in terms of allergenicities, birch pollen is almost the same as alder and beech and oak are partly different from the alder.
Conclusions: The Japanese respond to alder pollen just same as they do to birch pollen in forming specific IgE antibody. In clinical practice, positive alder RAST has the same meaning as positive birch RAST.
↩[4] - Ipsen H, Wihl JA, Petersen BN, Lowenstein H. Specificity mapping of patients IgE response towards the tree pollen major allergens Aln g I, Bet v I and Cor a I. Clin Exp Allergy 1992;22:391-399
The specificity pattern of IgE from non-treated tree pollen allergic patients (n = 38) were evaluated by solid phase absorption of serum samples followed by CRIE on alder, birch and hazel CIE precipitation profiles. The majority of the serum samples seemed to contain IgE antibodies with the following characteristics: specific towards Bet v I alone and common between Aln g I, Bet v I and/or Cor a I, 'II'. The IgE specificity profiles observed for 95% of the sera tested are compatible with birch pollen allergens being the only sensitizing allergens, indicating that the patients react to allergens from other tree pollens of the Fagales order due to IgE cross-reaction with the major allergens of birch and alder and/or hazel pollens.
↩[5] - Egger C, Focke M, Bircher A, Scherer K, Valenta R. Primary sensitisation to birch pollen in patients allergic to beech and oak pollen. EAACI 25th Congress, Vienna, 10-14 June, 2006, Poster n°277
Background and aims. Allergy to beech and oak pollen is frequently observed in northern and middle Europe and North America. Aim of our study was to investigate the allergen profile of beech and oak.
Methods. Sera from tree pollen allergic Swiss patients from an area with low birch pollen exposure (n=23) and Austrian patients with high birch pollen exposure (n=26) were analysed by immunoblot experiments and ELISA for IgE reactivity to birch (Betula pendula), beech (Fagus sylvatica) and oak (Quercus alba) pollen allergens. In addition, IgE inhibition experiments were performed with recombinant and purified natural allergens and allergen specific antibodies were used to identify beech and oak pollen allergens.
Results. Preincubation of sera with purified birch and grass pollen allergens (rBet v 1, rBet v 2, rPhl p 7 and nPhl p 4) identified allergens in beech and oak pollen which cross-react with Bet v 1 (17 kDa), profilin (14 kDa), a 2 EF-hand calcium-binding allergen (8 kDa) and Phl p 4 (> 35 kDa). These results were confirmed with allergen-specific antibodies. The majority (20/23) of the Swiss patients and all Austrian patients reacted with Bet v 1. Profilin was recognised by 6 Swiss and 6 Austrian patients, one Austrian patient showed reactivity to the 2 EF-hand allergen. Phl p 4-related immunoreactivity in beech and oak pollen was common in Swiss and Austrian patients. Quantitative assessment of IgE levels by ELISA showed highest IgE values for birch followed by beech and oak pollen in Austrian and Swiss patients.
Conclusions. Birch, beech and oak pollen contain cross-reactive allergens. Allergy to beech and oak pollen is mainly due to sensitisation to crossreactive birch pollen allergens. This should be considered when choosing immunotherapy for the treatment of tree pollen allergy.
↩[6] - Dohsaka Y, Maguchi S, Takagi S, Nagahashi T, Fukuda S, Inuyama Y. [Effect of oak pollen on patients with birch pollinosis]. Nippon Jibiinkoka Gakkai Kaiho 1995;98:357-361
The author reviewed 53 cases of birch pollinosis treated in our ENT-clinic between 1990 and 1991. Of interest is the fact that many of these patients complained of typical symptoms in and after June, when birch pollen has usually disappeared. We considered this discrepancy to be attributable to the effects of grass pollen, one of the common causal agents in this period. However, only a few patients tested positive for grass pollinosis. We therefore postulated that cross-reactivity between birch and oak pollen accounted for this phenomenon, because both trees belong to same order, Fagales. A strong correlation between RAST scores for birch and oak pollen was detected, and the oak pollen RAST score was significantly reduced by birch pollen extract in an inhibition test. These findings demonstrated actual cross-reactivity between birch and oak pollen. Birch pollinosis patients in Sapporo therefore have allergic symptoms from March to July.
↩[7] - Patriarca S, Voltolini S, Navone R, Martini S, Montanari C, Negrini A, et al. Biochemical and immunochemical characterization of hop-hornbeam (Ostrya Carpinifolia Scop.) pollen - A new allergenic pollen from the Corylaceae family. Aerobiologia 2000;16:255-260 ↩
[8] - Morita A, Inomata N, Kirino M, Ikezawa Z. [Correlation of oral allergy syndrome due to plant-derived foods with alder pollen, rBet v 1 and rBet v 2 sensitization in Yokohama region]. Arerugi 2008;57:138-146
BACKGROUND.AIM: Oral allergy syndrome (OAS) to plant foods is often caused by cross-reactivity to pollen. We investigated whether there was any significant correlation between sensitization to the pollen of alder and Japanese cedar flying off in spring and prevalence of OAS in Yokohama region.
METHODS: We measured specific IgE antibodies (CAP-FEIA: CAP) against alder and Japanese cedar in 337 outpatients with skin allergy in 2005 (M:F=167:170, 33.4 years of age, on the average). In the patients who showed positive response to CAP against alder and Japanese cedar, we also tested response to CAP against rBet v 1 and rBet v 2. In addition, we statistically analyzed whether there was any correlation between prevalence of OAS and sensitization to the pollen.
RESULTS: Ratio of positive response to CAP against alder was 23.4% (79 cases) while that to CAP against Japanese cedar was 73.7% (244 cases). Response to CAP against rBet v 1 and rBet v 2 was tested in 55 cases, and the ratio of positive response to CAP against rBet v 1 was 43.6% (24 cases) while that to CAP against rBet v 2 was 27.3% (15 cases). Prevalence of OAS showed a significant positive correlation (p<0.001) with sensitization to alder, but no correlation with sensitization to Japanese cedar.
CONCLUSION: It was suggested that sensitization to alder pollen would be involved in prevalence of OAS in Yokohama region.
↩[9] - Sjölander S, Urisu A, Ido T, Yagami A, Fukuda K, Horikawa T et al. Soy reactions in Japanese adults sensitised to Gly m 4 and alder pollen. Allergy 2009;64(Suppl. 90):371
Background: The PR-10 allergen of soybean, Gly m 4, has lately been associated with severe allergic reactions in pollen allergic individuals. In Europe, the cause of the reactions seems to be Gly m 4 related cross-reactions after a primary sensitization to the major birch pollen allergen Bet v 1. Studies regarding the incidence of Gly m 4 related soy reactions outside Europe are limited.
OBJECTIVE: The aim of the study was to study pollen allergic Japanese adults that had experienced reactions after intake of soy containing drinks or foods and to establish a possible connection between the reactions and IgE sensitization to Gly m 4. In addition, we wanted to indentify the primary sensitising pollen allergen in Japan.
METHODS: Fifteen pollen allergic Japanese adults (median age 41 years, 14 females and 1 male) experienced symptoms after intake of mainly soy milk but also soy containing foods like tofu and soybean sprouts. The symptoms included mainly OAS (11 individuals) but also urticaria (2) and anaphylaxis (2). Level of IgE serum antibody to extracts from soy and alder as well as recombinant Gly m 4 and Bet v 1 was measured using ImmunoCAP®. Results & Discussion: Analysis of serum antibody IgE responses to soy extract showed no significant levels in 8 of the 15 individuals (<0.35 kU/L) and the remaining 7 individuals responded with low levels (median level 0.7 kU/L). However, all individuals responded with significant levels to Gly m 4 (median level 9 kU/L) and Bet v 1 (median level 21 kU/L). IgE responses to alder were analysed, as alder but not birch are common in Japan and a close botanical relationship between the trees have been confirmed. All individuals responded with significant levels to alder (median level 18 kU/L).
CONCLUSION: In this study an association between the soy reactions and sensitization to the Gly m 4 allergen of soy was indicated. Further, we also hypothesize that the primary sensitizing allergen in Japan is the PR-10 allergen of alder, Aln g 1.
↩[10] - Patriarca S, Voltolini S, Navone R, Martini S, Montanari C, Negrini A, et al. Biochemical and immunochemical characterization of hop-hornbeam (Ostrya Carpinifolia Scop.) pollen - A new allergenic pollen from the Corylaceae family. Aerobiologia 2000;16:255-260 ↩
[11] - Camlek L, Korosec P, Kosnik M. Cross-reacting IgE antibodies in patients sensitized to birch and hornbeam pollen. EAACI 23th Congress, Amsterdam, 12-16 June, 2004, Poster n°204
Background: Patients with allergic rhinitis are often sensitized to both birch and hornbeam pollen as determined by skin prick tests and sIgE measurements. It would be useful to distinguish patients with true double sensitization and cross-reactivity to perform immunotherapy with the pollen antigens that induced the sensitization.
Methods: We investigated cross-reactors and non cross-reactors for birch and hornbeam pollen by FEIA inhibition test in 14 double (birch and hornbeam pollen) skin test positive patients. Inhibition over 80% was regarded as complete.
Results: Of 14 patients tested, 9 patients were completely cross-reacting for both birch and hornbeam pollen, while 4 patients were completely cross-reacting just for one pollen (3 birch and 1 hornbeam). A serum of 1 patient was partially cross-reacting for both pollens.
Conclusion: We show that majority of the selected patients was completely cross reacting for both pollens and that their primary sensitization cannot be determined. Three patients had primary sensitization due to birch pollen; one patient due to hornbeam pollen and one patient had primary sensitization due to both pollens. The FEIA inhibition should be considered a convenient tool for identification of primary sensitization in patients allergic to birch and hornbeam pollen.
↩[12] - Sparholt SH, Larsen JN, Ipsen H, Schou C, Van Neerven RJJ. Crossreactivity and T-cell epitope specificity of Bet v 1-specific T cells suggest the involvement of multiple isoallergens in sensitization to birch pollen. Clin Exp Allergy 1997;27:932-941
Allergen-specific T lymphocytes play an important role in the pathophysiology of atopic disease. Detailed studies of their epitope-specificity and crossreactivity are required for the development of novel approaches for specific immunotherapy.
Objectives The aim of the study was to characterize the fine specificity of Bet v 1-specific T cells from allergic donors.
Methods Polyclonal T-cell Lines (TCL) and T-cell clones (TCC), specific for Bet v 1, the major birch (Betula verrucosa) pollen allergen, were isolated from the peripheral blood of three birch-allergic patients. Their epitope-specificity was studied using overlapping synthetic peptides, and crossreactivity with other tree pollen allergens of the Fagales order was evaluated. In addition, the Bet v 1-specific TCC were studied for their phenotype and cytokine production.
Results All isolated Bet v 1-specific TCC (19/21 CD4(+), 2/21 CD8(+)) reacted with affinity purified Bet v 1, but showed different reactivities with recombinant Bet v 1 (rBet v 1), and with group 1 allergens from other Fagales species. Epitope mapping of rBet v 1-reactive TCC with synthetic peptides of Bet v 1 showed the presence of four T-cell epitopes. Polyclonal T-cell lines reacted with 13 different peptides, and displayed even broader crossreactivity with group 1 pollen allergens from other Fagales members.
Conclusion This study demonstrates that apart from T-cell epitopes of rBet v 1, many other crossreactive or Bet v 1 isoallergen-specific epitopes exist. This indicates that isoallergenic variation plays an important role in the induction of Bet v 1-specific and crossreactive T-cell responsiveness to allergens
↩[13] - Wallner M, Erler A, Hauser M, Klinglmayr E, Gadermaier G, Vogel L et al. Immunologic characterization of isoforms of Car b 1 and Que a 1, the major hornbeam and oak pollen allergens. Allergy 2009;64:452-460
BACKGROUND: Birch pollen allergy is one of the most common causes of spring pollinosis often associated with hypersensitivity reactions to pollen of other Fagales species. Yet, only the major disease eliciting allergens of alder and hazel have been fully characterized. Therefore, the aim of this study was to perform cloning, expression and immunologic characterization of the Bet v 1 homologues from oak (Que a 1) and hornbeam (Car b 1) .
METHODS: The isoform pattern of Car b 1 and Que a 1 was analyzed by proteomics using 2D gel electrophoresis and LC ESI-QTOF MS. Isoallergens showing high IgE-binding were cloned and expressed in Escherichia coli. IgE-binding activity of the recombinant proteins was determined by enzyme-linked immunosorbent assay (ELISA) and basophil mediator release assays using serum samples from patients mainly exposed either to oak and hornbeam or to birch pollen. Cross-reactivity of the allergens was further investigated at the T-cell level .
RESULTS: Dominant isoforms of Car b 1 and Que a 1, identified by mass spectrometry, showed different IgE-binding properties when testing Fagales pollen-allergic patients living in birch-free areas as compared to birch-sensitized individuals .
CONCLUSION: Tree pollen-allergic patients who are primarily exposed to Fagales pollen other than birch reacted stronger with rCar b 1 and rQue a 1 than with rBet v 1, as determined by inhibition ELISA and basophil mediator release assays. Thus, rCar b 1 and rQue a 1 allergens should be considered for improving molecule-based diagnosis and therapy of tree pollen allergies manifesting in birch-free areas.
↩[14] - Movérare R, Everberg H, Carlsson R, Holtz A, Thunberg R, Olsson P, et al. Purification and Characterization of the Major Oak Pollen Allergen Que a 1 for Component- Resolved Diagnostics Using ImmunoCAP. Int Arch Allergy Immunol 2008;146:203-211
BACKGROUND: The aim of this study was to purify the major oak pollen allergen, Que a 1, to perform biochemical and immunological characterization of the allergen and to develop an experimental native (n) Que a 1 ImmunoCAP(R) .
METHODS: Que a 1 was purified from oak pollen extract using affinity chromatography and characterized by SDS-PAGE, two-dimensional (2D) PAGE, mass spectrometry (MS), N-terminal sequencing and specific IgE inhibition on ImmunoCAP. Samples from 16 subjects sensitized to oak pollen were analyzed by ImmunoCAP for IgE reactivity to nQue a 1, and recombinant (r)Bet v 1 and 2 (profilin). They were also studied in IgE immunoblotting .
RESULTS: The purity of nQue a 1 was >95%, since a single band was observed on silver-stained SDS-PAGE. The identity was verified by MS analysis, and 2D-PAGE revealed several isoforms. The obtained N-terminal sequence of 50-amino-acid residues from nQue a 1 showed a 58-74% sequence identity with other pathogenesis-related class 10 allergens. Specific IgE inhibition verified a preserved immunoreactivity (70-92% inhibition). All subjects were sensitized to Que a 1 and Bet v 1, and two to profilin. The IgE antibody levels to nQue a 1 were generally lower than to rBet v 1. The obtained results correlated well with IgE immunoblotting .
CONCLUSIONS: We present a highly purified and extensively characterized preparation of nQue a 1. Que a 1 seems to be an allergen of equal importance in oak pollen as Bet v 1 in birch pollen. An nQue a 1 ImmunoCAP will be useful in component-resolved diagnostics.
↩[15] - Mari A, Wallner M, Ferreira F. Fagales pollen sensitization in a birch-free area: a respiratory cohort survey using Fagales pollen extracts and birch recombinant allergens (rBet v 1, rBet v 2, rBet v 4). Clin Exp Allergy 2003;33:1419-1428
BACKGROUND: Birch allergy is one of the most common pollinosis in areas where exposure to high levels of birch pollen is common. Little is known about birch sensitivity in areas without birch pollen exposure and reactivity to birch-related species within the Fagales order .
OBJECTIVE: the aim was to evaluate Fagales reactivity within a population not exposed to birch pollen using epidemiological, diagnostic, and laboratory approaches by means of extracts and allergenic molecules .
METHODS: A cohort of 5335 respiratory allergic patients was screened by means of skin testing birch, hazel, and oak pollen extracts. Patients were from a birch-free area, but exposed to other Fagales pollen species. A subset of patients was from an intensively cultivated hazel area. A sample of the Fagales allergic population was tested with other Fagales pollen extract (alder, hornbeam, beech, chestnut) and with apple and hazelnut. IgE detection was performed with birch, hazel, oak, apple, and hazelnut extracts, and with Bet v 1, Bet v 2, Bet v 4, and bromelain. IgE immunoblots were performed using birch and hazel extracts. Epidemiological, clinical, and laboratory data were analysed by stratifying the allergic population .
RESULTS: Twenty-five percent of the pollen allergic cohort was skin test positive to at least one of the three Fagales species. Combined reactivity to the three species was recorded in 80% of this cohort. Isolated hazel pollen reactivity was recorded in 13.5% of the Fagales allergic patients. Sixty-six percent of these subjects were from the intensively cultivated hazel area. Reactivity to apple and hazelnut was detected by skin test (40%) and IgE reactivity (60%), but only 19% of the positive patients reported symptoms related to at least one of the two foods. Reactivity to Bet v 1 was recorded in 84% of the birch/hazel/oak co-reactivity group, and in 28% of the subjects with the same co-reactivity, but associating a multiple pollen sensitization. IgE to Bet v 2 (50%) and Bet v 4 (23%) panallergens were recorded positive in the latter subset. Bet v 1 prevalence ranged between 48% and 21% among subgroups of patients coming from different areas. Furthermore, an IgE reactivity to hazel-restricted allergenic components was detected among subjects coming from the same area and having a hazel isolated reactivity .
CONCLUSION: Fagales allergy can be found in birch-free areas caused by the exposure to other Fagales species. Birch allergens can be useful for mimicking the allergenic extract, but are also the exclusive tools for a fine diagnostic and epidemiological approach to Fagales pollen allergy. Allergenic molecules from the hazel family will increase the panel of available reagents for the molecule-based approach to allergy diagnosis and therapy.
↩[16] - Metz-Favre C, Birba E, Metivier AC, de Blay F, Pauli G. Intérêt du dosage des IgE vis-à-vis de l'allergène recombinant rBet v 1 dans la prise en charge de la pollinose printanière. Rev Fr Allergol Immunol Clin 2005;45:584-589
Nous avons évalué le dosage des IgE spécifiques anti-rBet v 1 en tant que nouvel outil diagnostique dans la prise en charge de la pollinose printanière.
Méthodes. - Cent dix-sept dossiers de patients consultant en allergologie ont été sélectionnés sur la demande d'IgE anti-rBet v 1. Les motifs de consultation étaient variés. Des dosages d'IgE anti-rBet v 2 et antipollen de bouleau (t3) étaient présents respectivement dans 82 et 28 dossiers. Le diagnostic de pollinose au bouleau était établi sur une histoire clinique évocatrice associée à un test cutané positif à l'extrait de pollen de bouleau. La présence d'un syndrome oral a été recherchée chez 105 patients. L'association d'un asthme a été considérée comme un facteur de gravité de la pollinose.
Résultats. - Dans la population étudiée, la sensibilité, la spécificité, la VPP et la VPN du dosage d'IgE anti-rBet v 1 sont excellentes (respectivement de 91, 82, 92 et 93 %). Dans le groupe de patients ayant eu également des dosages d'IgE anti-t3, la sensibilité et la spécificité des IgE anti-rBet v 1 étaient supérieures à celles des IgE anti-t3. Lorsque les dosages d'IgE anti-rBet v 2 étaient effectués concomitamment, ils étaient positifs dans 19,5 % des cas avec une médiane de 2,46 KU/l. Le syndrome oral était plus fréquemment associé chez les patients ayant des taux d'IgE spécifiques anti-rBet v 1 supérieurs à 50 KU/l. Le dosage des IgE spécifiques rBet v 1 n'était en revanche pas un élément prédictif de l'association d'un asthme à la pollinose.
Conclusion. - Ce dosage permet de définir en partie le profil de sensibilisation des patients et de guider la désensibilisation.
↩[17] - Skypala I, Calderon M, Leeds A, Durham S. Pollen-food syndrome in United Kingdom subjects - which aeroallergens are commonly involved ? Allergy 2007;62(suppl. 83):358
Pollen food syndrome (PFS) is common in individuals with birch pollen sensitivity who present with hay fever symptoms in the spring. The aim of this study was to evaluate which pollen(s), apart from birch, are associated with PFS in UK-based subjects, and whether aero-allergen sensitivities differ in those subjects with springtime hay fever with/without associated PFS. Adult subjects reporting hay fever symptoms between March and May were included in the study. All subjects underwent skin prick testing with tree (birch, oak, beech, plane and three trees ˜ birch, alder and hazel), timothy grass, mugwort, latex, cat and house dust mite (D. pteronyssinus) allergens (ALK Abelló Denmark). A diagnosis of PFS was established for each subject using a combination of results from a standardised medical assessment, prick by prick testing with suspect foods and oral food challenge. 119 subjects completed the study; 92% were sensitised to one or more aeroallergens. Although all subjects reported spring and/or summer time hay fever, only 85% of the cohort were sensitised to pollen. Grass was the commonest sensitising pollen allergen (68%), followed by birch (64%), oak and three trees (53%), beech (34%), plane (26%) and mugwort (18%). Approximately half of the cohort were sensitised to cat and/or house dust mite, but less than 10% to latex. Subjects diagnosed with PFS had a significantly greater number of positive tests for birch, oak, beech (p<0.001) and grass (p<0.05) than those without PFS, but there was no significant difference between the groups for the other aeroallergens. Polysensitisation to pollen allergens occurred in 93% of the group diagnosed with PFS compared to 37% of the group without PFS. No aeroallergen sensitivities were individually or collectively significant predictors of the diagnosis of PFS although a combination of birch, grass and oak gave the best standardised beta coefficient. UK subjects with springtime hay fever are most likely to be sensitised to birch, grass and oak. The frequency of sensitivities to these allergens is greater in those who additionally have PFS. In contrast, subjects with/without PFS do not differ in their rate of sensitisation to cat and house dust mite. Sensitisation to pollen cannot predict who with springtime hay fever will have PFS, but those with PFS are more likely to be co-sensitised to several tree and grass pollens.
↩[18] - Wallner M, Erler A, Hauser M, Klinglmayr E, Gadermaier G, Vogel L et al. Immunologic characterization of isoforms of Car b 1 and Que a 1, the major hornbeam and oak pollen allergens. Allergy 2009;64:452-460
BACKGROUND: Birch pollen allergy is one of the most common causes of spring pollinosis often associated with hypersensitivity reactions to pollen of other Fagales species. Yet, only the major disease eliciting allergens of alder and hazel have been fully characterized. Therefore, the aim of this study was to perform cloning, expression and immunologic characterization of the Bet v 1 homologues from oak (Que a 1) and hornbeam (Car b 1) .
METHODS: The isoform pattern of Car b 1 and Que a 1 was analyzed by proteomics using 2D gel electrophoresis and LC ESI-QTOF MS. Isoallergens showing high IgE-binding were cloned and expressed in Escherichia coli. IgE-binding activity of the recombinant proteins was determined by enzyme-linked immunosorbent assay (ELISA) and basophil mediator release assays using serum samples from patients mainly exposed either to oak and hornbeam or to birch pollen. Cross-reactivity of the allergens was further investigated at the T-cell level .
RESULTS: Dominant isoforms of Car b 1 and Que a 1, identified by mass spectrometry, showed different IgE-binding properties when testing Fagales pollen-allergic patients living in birch-free areas as compared to birch-sensitized individuals .
CONCLUSION: Tree pollen-allergic patients who are primarily exposed to Fagales pollen other than birch reacted stronger with rCar b 1 and rQue a 1 than with rBet v 1, as determined by inhibition ELISA and basophil mediator release assays. Thus, rCar b 1 and rQue a 1 allergens should be considered for improving molecule-based diagnosis and therapy of tree pollen allergies manifesting in birch-free areas.
↩[19] - van Ree R, Van Leeuwen WA, Akkerdaas JH, Aalberse RC. How far can we simplify in vitro diagnostics for Fagales tree pollen allergy ? A study with three whole pollen extracts and purified natural and recombinant allergens. Clin Exp Allergy 1999;29:848-855
BACKGROUND: Current diagnostic tests for Fagales tree pollen allergy are often composed of mixtures of pollen of birch, alder and hazel. Their complex composition hampers accurate standardization .
OBJECTIVE: The aim of this study was to investigate whether mixtures of tree pollen extracts can be replaced by a single pollen species, and whether a single pollen species can be replaced by a limited number of purified natural or recombinant major allergens .
METHODS: Sera (n = 1725) were selected on ground of a general suspicion for inhalant allergy, and tested in a RAST for birch, alder and hazel pollen. Sera with > 0.5 RU/mL for any of the three species were tested in a RAST for natural Bet v 1 and Bet v 2 as well as for recombinant versions of both allergens .
RESULTS: Specific IgE antibodies (> 0.3 RU/mL) against birch, alder and hazel were found in 242, 298 and 292 sera, respectively. All sera with a positive RAST for alder and/or hazel and a negative RAST for birch were low-responder sera on alder and hazel, only five sera having a RAST value > 1.0 (all < 2.0). For all sera with a RAST > 0.5 RU/mL (n = 250), the mean of individual ratio's alder/birch and hazel/birch was 1.02 and 0.54, respectively. Of 223 of these sera, 63.2% had specific IgE against natural Bet v 1 and 63.7% against natural Bet v 2. When responses to both allergens were combined 93.7% were positive. The mean ratios Bet v 1 + 2/extract were 1.00, 1.04 and 2. 11 in case of birch, alder and hazel, respectively. For 211 sera the same analysis was performed with recombinant Bet v 1 and Bet v 2. Only six sera with Bet v 1-specific IgE (all < 0.5 RU/mL) were negative (< 0.3 RU/mL) on recombinant Bet v 1. For Bet v 2, 77/132 sera with specific IgE to the natural allergen did not react to the recombinant version. Twelve false-negatives had RAST values > 1.0 RU/mL. The mean of the individual recombinant/natural ratios was 0. 98 for Bet v 1 and 0.38 for Bet v 2 (P < 0.001). The mean ratio rBet v 1 + 2/birch was 0.75 with 17.5% false-negatives on the combination of recombinant allergens .
CONCLUSION: Reliable in vitro diagnosis is possible with a single tree pollen extract (birch or alder). The same is true for purified natural Bet v 1 and Bet v 2. A combination of recombinant molecules is slightly less efficient.
↩[20] - Cuesta-Herranz J, Lazaro M, Martinez A, Figueredo E, Palacios R, Delhaseras M, et al. Pollen allergy in peach-allergic patients: sensitization and cross-reactivity to taxonomically unrelated pollens. J Allergy Clin Immunol 1999;104:688-694
BACKGROUND: Fruit allergy has been attributed to cross-reactive IgE to pollens and has been associated with a particular pollen sensitization .
OBJECTIVE: The aim of the study was to evaluate sensitization to several taxonomically unrelated pollens in peach- and pollen-allergic patients and to study cross-reactivity between them .
METHODS: One hundred sixty-five patients were evaluated: 70 peach- allergic patients together with 95 pollen-allergic patients (control group). Pollen skin tests in duplicate were performed to 5 grasses, 8 trees, and 7 weeds. Cross-reactivity between peach and taxonomically diverse pollens was determined by radioallergosorbent inhibition and Western blot inhibition tests. Experiments were also carried out after preadsorption of the sera with purified natural profilin .
RESULTS: The skin test results revealed that peach-allergic patients frequently reacted to most pollens-grasses, weeds, and trees-even when some of these are not found in our geographic area. There was a statistically significant increase in sensitization frequency to most trees and weeds, with a statistically higher occurrence of asthma (odds ratio 2.98, 95% confidence interval 1.46-6.09). Inhibition test results provided evidence that taxonomically unrelated grasses, weeds, and trees produced various and substantial degrees of inhibition in specific IgE to peach and that the peach extract elicited strong inhibitions to those pollens. Profilin was found to be a relevant cross-reactive antigen in these patients .
CONCLUSION: The results of this study provide evidence that peach allergy is linked to sensitization to several taxonomically unrelated pollens. This is attributable to the ubiquitous nature of the IgE binding determinants-such as profilins-between peach and taxonomically unrelated pollens.
↩[21] - Mari A, Wallner M, Ferreira F. Fagales pollen sensitization in a birch-free area: a respiratory cohort survey using Fagales pollen extracts and birch recombinant allergens (rBet v 1, rBet v 2, rBet v 4). Clin Exp Allergy 2003;33:1419-1428
BACKGROUND: Birch allergy is one of the most common pollinosis in areas where exposure to high levels of birch pollen is common. Little is known about birch sensitivity in areas without birch pollen exposure and reactivity to birch-related species within the Fagales order .
OBJECTIVE: the aim was to evaluate Fagales reactivity within a population not exposed to birch pollen using epidemiological, diagnostic, and laboratory approaches by means of extracts and allergenic molecules .
METHODS: A cohort of 5335 respiratory allergic patients was screened by means of skin testing birch, hazel, and oak pollen extracts. Patients were from a birch-free area, but exposed to other Fagales pollen species. A subset of patients was from an intensively cultivated hazel area. A sample of the Fagales allergic population was tested with other Fagales pollen extract (alder, hornbeam, beech, chestnut) and with apple and hazelnut. IgE detection was performed with birch, hazel, oak, apple, and hazelnut extracts, and with Bet v 1, Bet v 2, Bet v 4, and bromelain. IgE immunoblots were performed using birch and hazel extracts. Epidemiological, clinical, and laboratory data were analysed by stratifying the allergic population .
RESULTS: Twenty-five percent of the pollen allergic cohort was skin test positive to at least one of the three Fagales species. Combined reactivity to the three species was recorded in 80% of this cohort. Isolated hazel pollen reactivity was recorded in 13.5% of the Fagales allergic patients. Sixty-six percent of these subjects were from the intensively cultivated hazel area. Reactivity to apple and hazelnut was detected by skin test (40%) and IgE reactivity (60%), but only 19% of the positive patients reported symptoms related to at least one of the two foods. Reactivity to Bet v 1 was recorded in 84% of the birch/hazel/oak co-reactivity group, and in 28% of the subjects with the same co-reactivity, but associating a multiple pollen sensitization. IgE to Bet v 2 (50%) and Bet v 4 (23%) panallergens were recorded positive in the latter subset. Bet v 1 prevalence ranged between 48% and 21% among subgroups of patients coming from different areas. Furthermore, an IgE reactivity to hazel-restricted allergenic components was detected among subjects coming from the same area and having a hazel isolated reactivity .
CONCLUSION: Fagales allergy can be found in birch-free areas caused by the exposure to other Fagales species. Birch allergens can be useful for mimicking the allergenic extract, but are also the exclusive tools for a fine diagnostic and epidemiological approach to Fagales pollen allergy. Allergenic molecules from the hazel family will increase the panel of available reagents for the molecule-based approach to allergy diagnosis and therapy.
↩[22] - Mari A, Wallner M, Ferreira F. Fagales pollen sensitization in a birch-free area: a respiratory cohort survey using Fagales pollen extracts and birch recombinant allergens (rBet v 1, rBet v 2, rBet v 4). Clin Exp Allergy 2003;33:1419-1428
BACKGROUND: Birch allergy is one of the most common pollinosis in areas where exposure to high levels of birch pollen is common. Little is known about birch sensitivity in areas without birch pollen exposure and reactivity to birch-related species within the Fagales order .
OBJECTIVE: the aim was to evaluate Fagales reactivity within a population not exposed to birch pollen using epidemiological, diagnostic, and laboratory approaches by means of extracts and allergenic molecules .
METHODS: A cohort of 5335 respiratory allergic patients was screened by means of skin testing birch, hazel, and oak pollen extracts. Patients were from a birch-free area, but exposed to other Fagales pollen species. A subset of patients was from an intensively cultivated hazel area. A sample of the Fagales allergic population was tested with other Fagales pollen extract (alder, hornbeam, beech, chestnut) and with apple and hazelnut. IgE detection was performed with birch, hazel, oak, apple, and hazelnut extracts, and with Bet v 1, Bet v 2, Bet v 4, and bromelain. IgE immunoblots were performed using birch and hazel extracts. Epidemiological, clinical, and laboratory data were analysed by stratifying the allergic population .
RESULTS: Twenty-five percent of the pollen allergic cohort was skin test positive to at least one of the three Fagales species. Combined reactivity to the three species was recorded in 80% of this cohort. Isolated hazel pollen reactivity was recorded in 13.5% of the Fagales allergic patients. Sixty-six percent of these subjects were from the intensively cultivated hazel area. Reactivity to apple and hazelnut was detected by skin test (40%) and IgE reactivity (60%), but only 19% of the positive patients reported symptoms related to at least one of the two foods. Reactivity to Bet v 1 was recorded in 84% of the birch/hazel/oak co-reactivity group, and in 28% of the subjects with the same co-reactivity, but associating a multiple pollen sensitization. IgE to Bet v 2 (50%) and Bet v 4 (23%) panallergens were recorded positive in the latter subset. Bet v 1 prevalence ranged between 48% and 21% among subgroups of patients coming from different areas. Furthermore, an IgE reactivity to hazel-restricted allergenic components was detected among subjects coming from the same area and having a hazel isolated reactivity .
CONCLUSION: Fagales allergy can be found in birch-free areas caused by the exposure to other Fagales species. Birch allergens can be useful for mimicking the allergenic extract, but are also the exclusive tools for a fine diagnostic and epidemiological approach to Fagales pollen allergy. Allergenic molecules from the hazel family will increase the panel of available reagents for the molecule-based approach to allergy diagnosis and therapy.
↩[23] - Jato V, Aira MJ, Dopazo A, Iglesias MI, Méndez J, Rodriguez FJ. Aerobiology of Castanea pollen in Galicia. Aerobiologia 2001;17:233-240 ↩
[24] - Cosmes Martin PM, Moreno Ancillo A, Dominguez Noche C, Gutierrez Vivas A, Belmonte Soler J, Roure Nolla JM. [Sensitization to Castanea sativa pollen and pollinosis in northern Extremadura (Spain)]. Allergol Immunopathol (Madr) 2005;33:145-150
BACKGROUND: Castanea sativa pollen allergy has generally been considered to be uncommon and clinically insignificant. In our geographical area (Plasencia, Caceres, Spain) Castanea sativa pollen is a major pollen. OBJECTIVE: To determine the atmospheric fluctuations and prevalence of patients sensitized to Castanea pollen in our region and to compare this sensitization with sensitizations to other pollens.
METHODS: Patients with respiratory symptoms attending our outpatient clinic for the first time in 2003 were studied. The patients underwent skin prick tests with commercial extracts of a battery of inhalants including Castanea sativa pollen. Serologic specific IgE to Castanea sativa pollen was determined using the CAP system (Pharmacia and Upjohn, Uppsala, Sweden). Airborne pollen counts in our city were obtained using Cour collection apparatus over a 4-year period (2000 to 2003).
RESULTS: The most predominant pollens detected were (mean of the maximal weekly concentrations over 4 years in pollen grains/m3): Quercus 968, Poacea 660, Olea 325, Platanus 229, Pinus 126, Cupresaceae 117, Plantago 109, Alnus 41, Populus 40, Castanea 32. We studied 346 patients (mean age: 24.1 years). In 210 patients with a diagnosis of pollinosis, the percentages of sensitization were: Dactylis glomerata 80.4%, Olea europea 71.9%, Fraxinus excelsior 68%, Plantago lanceolata 62.8%, Chenopodium album 60.9%, Robinia pseudoacacia 49%, Artemisia vulgaris 43.8%, Platanus acerifolia 36.6%, Parietaria judaica 36.1%, Populus nigra 32.3%, Betula alba 27.6%, Quercus ilex 21.4%, Alnus glutinosa 20.9%, Cupressus arizonica 7.6% and Castanea sativa 7.1%. Fifteen patients were sensitized to Castanea sativa and 14 had seasonal rhinoconjunctivitis and asthma. Ten patients had serum specific IgE to Castanea pollen (maximum value: 17.4 Ku/l). Castanea pollen is present in our area in large amounts from the 23rd to the 28th weeks of the year, with a peak pollen count in the 25th week.
CONCLUSIONS: The most important allergenic pollens in northern Extremadura were Poaceae, Olea europaea and Plantago sp. The prevalence of sensitization to Castanea sativa pollen was very low (7.1%). Most sensitized patients had asthma and polysensitization. Castanea sativa pollen is not a major cause of pollinosis in our area.
↩[25] - Kos T, Hoffmann-Sommergruber K, Ferreira F, Hirschwehr R, Ahorn H, Horak F, et al. Purification, characterization and N-terminal amino acid sequence of a new major allergen from European chestnut pollen--Cas s 1. Biochem Biophys Res Commun 1993;196:1086-1092
Pollens from trees of the order Fagales (e.g. birch, alder, hazel, and hornbeam) all contain one major allergen--the main cause for tree pollen allergy. So far the major allergens from birch (Bet v 1), alder (Aln g 1), hazel (Cor a 1), and hornbeam (Car b 1) have been characterized, showing high sequence similarity with each other (1-4). We present the molecular and immunologic characterization of Cas s 1, the major allergen from the European chestnut (Castanea sativa). From aqueous pollen extracts from European chestnut a protein was purified to homogeneity and was subjected to further investigation. The protein revealed a Mr of 22 kDa and was shown to represent the major allergen of the European chestnut (immunoblotting, histamine release) and designated Cas s 1. Despite a marked difference in Mr, Cas s 1 shows significant amino acid sequence similarity at the N-terminus and is antigenically closely related to the major birch pollen allergen Bet v 1 (17 kDa), as shown by binding to the anti-Bet v 1 monoclonal antibody BIP-1 and by IgE-inhibition tests using recombinant Bet v 1.
↩[26] - Egger C, Focke M, Bircher AJ, Scherer K, Mothes-Luksch N, Horak F, et al. The allergen profile of beech and oak pollen. Clin Exp Allergy 2008;38:1688-1696
Imprimer la bibliographieBACKGROUND: Beech and oak pollen are potential allergen sources with a world-wide distribution .
OBJECTIVE: We aimed to characterize the allergen profile of beech and oak pollen and to study cross-reactivities with birch and grass pollen allergens .
METHODS: Sera from tree pollen-allergic patients with evidence for beech and oak pollen sensitization from Basel, Switzerland, (n=23) and sera from birch pollen-allergic patients from Vienna, Austria, (n=26) were compared in immunoblot experiments for IgE reactivity to birch (Betula pendula syn. verrucosa), beech (Fagus sylvatica) and oak (Quercus alba) pollen allergens. Subsequently, beech and oak pollen allergens were characterized by IgE inhibition experiments with purified recombinant and natural allergens and with allergen-specific antibody probes. Birch-, beech- and oak pollen-specific IgE levels were determined by ELISA .
RESULTS: Beech and oak pollen contain allergens that cross-react with the birch pollen allergens Bet v 1, Bet v 2 and Bet v 4 and with the berberine bridge enzyme-like allergen Phl p 4 from timothy grass pollen. Sera from Swiss and Austrian patients exhibited similar IgE reactivity profiles to birch, beech and oak pollen extracts. IgE levels to beech and oak pollen allergens were lower than those to birch pollen allergens .
CONCLUSION: IgE reactivity to beech pollen is mainly due to cross-reactivity with birch pollen allergens, and a Phl p 4-like molecule represented another predominant IgE-reactive structure in oak pollen. The characterization of beech and oak pollen allergens and their cross-reactivity is important for the diagnosis and treatment of beech and oak pollen allergy.
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