Wheat omega-5 gliadin is a major allergen in children with immediate allergy to ingested wheat

Background: Sensitization to wheat by ingestion can lead to food allergy sy mptoms and wheat-dependent, exercise-induced anaphylaxis. Sensitization by inhalation causes bakers' asthma and rhinitis. Wheat allergens have been ch aracterized at the molecular level in bakers' asthma and in wheat-dependent , exercise-induced anaphylaxis, in which omega -5 gliadin (Tri a 19) is a m ajor allergen. However, little information is available regarding allergens responsible for hypersensitivity reactions to ingested wheat in children. Objective: The aim of this study was to examine whether children with aller gy to ingested wheat have IgE antibodies to omega -5 gliadin. Methods: Sera were obtained from 40 children (mean age, 2.5 years; range, 0 .7-8.2 years) with suspected wheat allergy who presented with atopic dermat itis and/or gastrointestinal and/or respiratory symptoms. Wheat allergy was diagnosed with open or double-blinded, placebo-controlled oral wheat chall enge. Wheat omega -5 gliadin was purified by reversed-phase chromatography, and serum IgE antibodies to omega -5 gliadin were measured by means of ELI SA. In vivo reactivity was studied by skin prick testing. Control sera were obtained from 22 children with no evidence of food allergies. Results: In oral wheat challenge, 19 children (48%) reacted with immediate and 8 children (20%) with delayed hypersensitivity, symptoms. Sixteen (84%) of the children with immediate symptoms had IgE antibodies to purified ome ga -5 gliadin in ELISA. In contrast, IgE antibodies to omega -5 gliadin wer e not detected in any of the children with delayed or negative challenge te st results or in the control children. The diagnostic specificity and posit ive predictive value of omega -5 gliadin ELISA were each 100% for immediate challenge reactions. Skin prick testing with w-5 gliadin was positive in 6 of 7 children with immediate challenge symptoms and negative in 2 children with delayed challenge symptoms. Conclusion: The results of this study show that omega -5 gliadin is a signi ficant allergen in young children with immediate allergic reactions to inge sted wheat. IgE testing with omega -5 gliadin could be used to reduce the n eed for oral wheat challenges in children.