Abdel-Gadir A, et al. - Researchers intended to determine the immune mechanisms mediating the successful desensitization of patients with food allergies with oral immunotherapy (OIT). In this regard, they tested the hypothesis that allergen-specific regulatory T (Treg) cell function is impaired in food allergy and is restored by anti-IgE antibody (omalizumab)-supplemented OIT. They found that allergen desensitization was promoted by OIT supplemented by omalizumab. This effect was induced via an initial omalizumab-dependent step that acutely depleted allergen-reactive T cells, followed by an increase in allergen-specific Treg cell activity due to the reversal of their Th2 cell-like programme. Overall, OIT ameliorates food allergy via improving Treg cell function (a key mechanism).