D2.214 - Alpha-Amylase Inhibitors as Allergens in Wheat Flour Sensitivity

Flour allergies can present unique challenges in identifying specific allergens, particularly when symptoms occur inconsistently. This study investigates the allergenic profiles of various flours in a 73-year-old patient with suspected sensitivity to wheat flour consumed in specific settings.

A 73-year-old male experienced recurrent urticaria after consuming sandwiches at a specific establishment, despite tolerating homemade bread and other wheat-based products. Skin tests were inconclusive, showing a weak positive for gliadin. Immunological assays indicated sensitization to specific wheat components, prompting further investigation.

Protein extracts were prepared from flours of wheat, barley, rye, rice, buckwheat, and wheat bran using PBS homogenization, centrifugation, and filtration. SDS-PAGE and Western blot analyses were conducted under reducing conditions to determine protein and allergenic profiles. IgE reactivity was evaluated using the patient’s serum.

Western blot analysis revealed IgE binding to proteins in the 13–15 kDa range across all flour samples, corresponding to alpha-amylase inhibitors. Additionally, a unique 25 kDa protein in buckwheat flour was recognized, which has not been previously described in allergenic literature. Gliadin, typically in the 30–80 kDa range, showed no significant IgE binding, ruling out its involvement in the observed reactions.

This study identifies alpha-amylase inhibitors as the likely allergenic triggers in the patient’s recurrent reactions, with a possible novel allergen in buckwheat flour. These findings emphasize the importance of comprehensive allergenic profiling to guide dietary recommendations and avoid misdiagnosis. Further research is needed to explore the implications of the newly identified protein in buckwheat.