ABROGATE - Stratification of patients with wheat allergy

Food allergies occur particularly under the influence of cofactors such as physical exertion, acetylsalicylic acid (aspirin, ASA), stress, infections, and alcohol. Food-dependent exercise-induced anaphylaxis (FDEIA) is a common IgE-mediated variant that occurs when the allergic reaction only occurs in the presence of such cofactors. The symptoms of FDEIA begin 30–480 minutes after food intake followed by cofactors and range from urticaria to anaphylactic shock. Wheat-dependent FDEIA (WDEIA) is the best-studied model disease for this variant of food allergy. The main allergen responsible for WDEIA is ω5-gliadin. Physical exertion, as a cofactor of food allergy, lowers the reaction threshold and increases the severity of the reaction. However, the underlying pathophysiology of WDEIA is not yet fully understood.

The aim of the project was to investigate mechanisms of food sensitization and allergy that allow predisposed individuals and prevention targets for the development of wheat allergy via the skin and intestines to be identified.

First, WDEIA patients were characterized and divided into four groups: 1) allergic WDEIA_gut, 2) allergic WDEIA_skin, 3) sensitized (IgE) but clinically tolerant patients (IgE_Sens), and 4) tolerant patients without detectable IgE antibodies (IgE_abs). For this purpose, allergenic test solutions consisting of gluten, wheat protein hydrolysates, and isolated gluten fractions and gluten protein types were provided for the basophil activation test (BAT). In the BAT, ω5-gliadins and high molecular weight glutenin subunits (HMW-GS) and a weakly hydrolyzed wheat protein showed the best results in terms of sensitivity and specificity in discriminating between WDEIA patients and control subjects.

Three epitopes known to cause WDEIA were identified in HMW-GS in a rye bread to which a WDEIA patient had reacted. These epitopes occur in both wheat and rye. The supplementary Western blot analysis showed a reaction of proteins from whole wheat flour, whole rye flour, and secalins with the serum of the WDEIA patient. In the other foods examined, the gluten content in baked goods ranged from 6.1 g/100 g (bread) to 14.3 g/100 g (rolls) and in breaded meat products to 1.1 g/100 g. No gluten was detected in shower gel and shampoo.

In addition, the concentrations of gliadin in tape strip samples from the skin of WDEIA patients were determined after atopy patch testing with wheat gluten, weakly hydrolyzed wheat protein, and a liquid hydrolyzed wheat gluten preparation. Differences in percutaneous absorption were observed depending on the gluten preparation, the strip, and the patient. Overall, the results contribute to further elucidation of the pathophysiology of WDEIA. Insgesamt leisten die Ergebnisse einen Beitrag zur weiteren Aufklärung der Pathophysiologie von WDEIA.