IgE antibodies to ω-5 gliadin associate with immediate symptoms on oral wheat challenge in Japanese children

Gliadins have been implicated in immunoglobulin E (IgE)-mediated allergy to ingested wheat and ω-5-gliadin is known to represent a major allergen in wheat-dependent exercise-induced anaphylaxis. Less known is whether ω-5-gliadin is a clinically relevant allergen in children with immediate allergy to ingested wheat. This study investigates whether specific IgE antibodies to ω-5-gliadin (sIgE-ω-5-gliadin-ab) could be used as a marker for oral wheat challenge outcome in wheat-sensitized children. A secondary objective was to study whether the level of sIgE-ω-5-gliadin was related to symptom severity in children with a positive challenge test. Serum samples from 88 children sensitized to wheat, of whom 35 underwent wheat challenge, were collected consecutively. sIgE-ω-5-gliadin-ab was related to a physician's diagnosis of wheat allergy and challenge symptoms. The mean concentration of sIgE-ω-5-gliadin-ab was 7.25 kUA/l in patients with wheat allergy and 1.08 kUA/l in patients with no wheat allergy (P < 0.01). sIgE-ω-5-gliadin-ab was only detected in 12 of the non-wheat allergic children and 11 of them had a specific IgE to wheat below 1.30 kUA/l. Children reacting with severe symptoms upon challenge (n = 8) had increased levels of sIgE-ω-5-gliadin-ab compared to children with moderate, mild or no symptoms (P < 0.001). The presence of sIgE-ω-5-gliadin-ab is related to the reaction level to wheat challenge outcome in wheat-sensitized children. The sIgE-ω-5-gliadin-ab was found to be associated with a strong convincing history of wheat allergy also in those cases when oral food challenge was avoided. The sIgE-ω-5-gliadin-ab level may serve as a marker for clinical reactivity in wheat-sensitized individuals.