Identification of a Candidate IgE‐Binding Maize Protein in a Patient With Corn‐Dependent Exercise‐Induced Anaphylaxis: A Case Report

Corn‐dependent exercise‐induced anaphylaxis (food‐dependent exercise‐induced anaphylaxis [FDEIA]) is rare, and its causative allergens remain poorly defined. Here, we report a case of corn‐dependent FDEIA and investigate candidate IgE‐binding proteins using immunological and proteomic analyses. A 13‐year‐old boy with a history of buckwheat allergy developed recurrent anaphylaxis during exercise after ingesting corn‐containing foods. An exercise challenge after ingesting 272 g of sweet corn reproduced the symptoms and confirmed the diagnosis. Corn‐specific IgE was 3.72 UA/mL, and skin prick testing was positive. IgE immunoblotting revealed patient‐specific bands at ~45 and 60 kDa. Two‐dimensional immunoblotting and mass spectrometry identified globulin‐1S (GLB1) and other proteins as candidate IgE‐binding proteins in this patient. Sequence analysis revealed significant local sequence similarity between maize GLB1 and buckwheat Fag e 5 within the second cupin domain. These findings identify GLB1 as a candidate IgE‐binding protein in this patient with corn‐dependent FDEIA. Although sequence similarities were observed between maize GLB1 and buckwheat Fag e 5, their immunological and clinical significance remains unclear, and further studies are required to determine whether cross‐reactivity exists.