IFNG and food allergy: Although increased production of IgE and Th2 cytokines (IL-4, IL-5 and IL-13) are considered common markers of food allergy [4], absence of IgE or increased levels of Th1 cytokines (IL-2, IFN-γ and TNF-α) have also been observed in several instances of food allergy [5,6], mainly in response to cow's milk [7,8].