These results indicate that OIT-mediated expansion of the circulating Treg population (possibly derived from mucosal compartments) contributes to the suppression of allergic reactions (e.g., systemic and skin symptoms); this suppression occurs through the reduction of both allergen-specific IgE production and degranulation of MCs and basophils (Fig. 3d and Supplementary Fig. 3). This evidence concerns the gene IGHE and allergic disease.