IL4 and food allergy: Our previous studies in food allergy, using clinical samples as well as murine models, have shown that IgG, in an FcγRIIb-dependent manner, can suppress both immediate mast cell and basophil activation by IgE:allergen and the induction of systemic Th2-adaptive immune responses by mast cell-derived IL-4 in allergen-exposed mice [25,26,28].