Patients with
wheat-dependent, exercise-induced anaphylaxis experience severe
allergic reactions when exercising after ingestion of wheat. The major wheat
allergen associated with these reactions is a omega-5
gliadin, and patients following a
gluten-free diet have remained free of symptoms. The aim of this study was to examine whether
allergens cross-reacting with
wheat omega-5 gliadin are present in rye, barley and oats. Sera from 23 adult patients with
wheat-dependent, exercise-induced anaphylaxis were examined. Cereal
allergens cross-reacting with
wheat omega-5 gliadin were identified by immunoblot inhibition. The cross-reactive
allergens were purified by gel filtration and reversed-phase chromatography and submitted to
amino acid sequencing. Cross-reactivity was further studied by
IgE ELISA and ELISA inhibition, and in vivo reactivity by skin prick testing. In immunoblotting rabbit anti-omega-5
gliadin antibodies bound to 70 kDa and 32 kDa
proteins in rye and a 34-kDa
protein in barley, but not to
proteins in oats. N-terminal sequencing identified these
proteins as rye gamma-70
secalin, rye gamma- 35
secalin and barley gamma-3
hordein, correspondingly. In ELISA 21/23 (91%) patients with
wheat-dependent, exercise-induced anaphylaxis showed
IgE antibodies to purified gamma-70
secalin, 19/23 (83%) to gamma-35
secalin and 21/23 (91%) to gamma-3
hordein. In ELISA inhibition omega-5
gliadin inhibited over 90% of the
IgE binding of pooled patient sera to solid-phase gamma-
secalins and gamma-3
hordein. Skin prick testing gave positive reactions to gamma-70
secalin in 10/15 (67%) patients, to gamma-35
secalin in 3/15 (20%) patients and to gamma-3
hordein in 7/15 (47%) patients. The results of this study show that gamma-70 and gamma-35
secalins in rye and gamma-3
hordein in barley cross-react with omega-5
gliadin, a major
allergen in
wheat-dependent, exercise-induced anaphylaxis. These findings suggest that also rye and barley may elicit symptoms in patients with
wheat-dependent, exercise-induced anaphylaxis.