Multiple Allergen Simultaneous Test for Food Allergens Cannot Screen Wheat-Dependent, Exercise-Induced Anaphylaxis and α-Gal Syndrome

Screening tests for specific immunoglobulin E (sIgE) to food allergens, such as the multiple allergen simultaneous test (MAST), are widely used in patients with suspected food allergies in South Korea. We evaluated whether MAST could effectively screen wheat-dependent exercise-induced anaphylaxis (WDEIA) and α-gal syndrome (AGS). We retrospectively reviewed patients with WDEIA and AGS diagnosed with unequivocal history and positive sIgE results for omega-5 gliadin and α-gal using ImmunoCAP, respectively. The clinical manifestations and results of MAST and ImmunoCAP (sIgE to wheat for WDEIA and beef/pork for AGS) were reviewed. In the MAST and ImmunoCAP results, class 0 (<0.35 units in each test) was considered negative. Medical records of 45 patients with WDEIA and 39 patients with AGS were reviewed. For WDEIA, 37 (82.2%) of patients had a history of anaphylaxis. Among those positive for omega-5 gliadin sIgE, 39 (87.7%) and 25 (55.6%) tested positive for gluten- and wheat-sIgE using ImmunoCAP, respectively. MAST performed on 15 patients yielded positive results for wheat-sIgE in 5 (33.3%). For AGS, 23 (59.0%) of patients had a history of anaphylaxis. Among those positive for α-gal sIgE, 32 (85.7%) and 37 (96.4%) tested positive for pork- and beef-sIgE using ImmunoCAP, respectively, whereas MAST could not detect sIgE for pork and beef (0%, 0/17). MAST for sIgE to food allergens cannot screen WDEIA and AGS. The tests for sIgE to a specific component of food allergen, such as omega-5 gliadin for WDEIA and α-gal for AGS, should be used to screen WDEIA and AGS.