Heat Processing Reduces IgE Binding but Not Basophil Sensitivity to Pea Proteins in Pea-Allergic Children

Background/Objectives: The increasing use of pea protein in plant-based foods raises concerns about IgE-mediated reactions, particularly in individuals sensitized to peanut. Knowledge on clinically relevant pea allergens and the impact of heat processing remains limited. This study investigated how thermal treatment affects the IgE binding and functional allergenicity of pea proteins in children with a confirmed pea allergy, with or without a concomitant peanut allergy. Methods: Serum from 11 patients was analyzed using SDS-PAGE, Western blotting, and an indirect basophil activation test (iBAT). Results: All patients showed IgE binding to Pis s 1 and PA2a/b in raw pea extract, with variable sensitization to Pis s 2 and mitogenic lectin. Heating (120 °C, 5 min) markedly reduced IgE binding and eliminated detectable IgE to Legumin S and ML. Despite this reduction, basophil sensitivity did not decrease; in several patients, EC50 values significantly decreased, indicating increased basophil responsiveness to heated pea. Patients with IgE profiles dominated by Pis s 1 and PA2a/b were most likely to show enhanced basophil activation after heating. Conclusions: These findings demonstrate that heat-stable vicilin subunits and albumins can maintain functional allergenicity despite reduced IgE recognition, underscoring the need for diagnostic approaches that incorporate processed food allergens.