Fast omega-gliadin is a major allergen in wheat-dependent exercise-induced anaphylaxis.
BACKGROUND
Wheat-dependent exercise-induced anaphylaxis is an anaphylaxy induced by physical exercise after ingestion of wheat. An immediate-type hypersensitivity to water/salt-insoluble fraction of wheat proteins (gluten) has been considered to underlie in this disease.


OBJECTIVE
The aim of the study is to determine the major allergen in Japanese patients with wheat-dependent exercise-induced anaphylaxis by using a panel of purified wheat gliadins and glutenins.


METHODS
Water/salt-insoluble wheat proteins, alpha-gliadin, beta-gliadin, gamma-gliadin, fast omega-gliadin, slow omega-gliadin, high molecular weight glutenin and low molecular weight glutenin, were purified, and five patients with wheat-dependent exercise-induced anaphylaxis, whose diagnose had been determined by positive-challenge test, were evaluated for skin prick test, dot-blotting test and CAP-RAST inhibition test by using these purified wheat proteins.


RESULTS
The fast omega-gliadin was the most potent allergen among these water/salt-insoluble proteins when evaluated by skin prick test and dot-blotting test. Fast and slow omega-gliadin, and gamma-gliadin caused dose-dependent inhibition of the serum IgE-binding to solid-phase gluten in the patients. The incubation with fast omega-gliadin of the patient's serum caused dose-dependent inhibition in the IgE-binding to gamma-gliadin as well as slow omega-gliadin, indicating a cross-reactivity of these proteins in IgE-binding.


CONCLUSIONS
We concluded that fast omega-gliadin is a major allergen among these water/salt-insoluble proteins for wheat-dependent exercise-induced anaphylaxis in Japanese patients, and IgE against fast omega-gliadin cross-reacts to gamma-gliadin and slow omega-gliadin.
Department of Dermatology, Shimane Medical University, Enya-cho 89-1, 693-8501, Shimane, Izumo, Japan. emorita@shimane-med.ac.jp
E
E
Morita
H
H
Matsuo
S
S
Mihara
K
K
Morimoto
A W J
AW
Savage
A S
AS
Tatham
D000293:Adolescent; D000328:Adult; D000485:Allergens; D000707:Anaphylaxis / Q000209:etiology* / Q000503:physiopathology*; D015444:Exercise; D005260:Female; D005903:Gliadin / Q000276:immunology* / Q000633:toxicity; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000276:immunology; D012882:Skin Tests; D014908:Triticum / Q000276:immunology*
D000485:Allergens; C078659:omega(1)-gliadin; D007073:Immunoglobulin E; D005903:Gliadin