Heat-treated egg allergens show lower basophil activation: A path toward safer oral immunotherapy

Oral immunotherapy (OIT) is a promising approach for treating IgE-mediated food allergy, but safety concerns limit its use. Heat-denaturation of food allergens may reduce allergic reactions by lowering IgE binding. Here, we examined how heat-induced structural changes in egg allergens affected basophil activation in egg-allergic patients.

Gal d 1 and Gal d 2 were subjected to heat treatment and analyzed for structural changes using SDS-PAGE, ELISA, NanoDSF, and circular dichroism. Peripheral blood samples were obtained from a cohort of 42 patients with egg allergy. Patients' sensitization status was determined, and basophils were isolated and incubated with native or heat-denatured egg allergen preparations. Basophil activation was assessed by measuring leukotriene release as a marker of degranulation.

Heat-denaturation induced time- and temperature-dependent structural changes in both Gal d 1 and Gal d 2, resulting in reduced IgE binding capacity. In functional assays, heat-denatured allergens elicited weaker basophil degranulation responses compared to native allergens, but the effect varied depending on individual IgE sensitization profiles. Among patients who reacted to heat-denatured allergens, egg-white IgE levels tended to be higher, although requiring higher doses to trigger leukotriene release.

Heat-denaturation of egg allergens reduces IgE-binding and basophil activation, although residual reactivity persists in patients with higher sensitization profiles. Importantly, higher allergen doses were needed to trigger basophil degranulation compared to native allergens, indicating a reduction in allergenic potency. These findings highlight the potential of heat-denatured egg allergens as safer starting materials for OIT, particularly within personalized, stepwise desensitization protocols, warranting further clinical investigation.