IFNG and autoimmune disease: Cytokines secreted by type 1 helper T (Th1) cells including IFN-γ and IL-2 are decreased under Zn2+ deficiency, suggesting an impairment of Th1 function [193,194], while one function of IFN-γ is to inhibit the development of the Th17 cells [180], which play a significant role in autoimmune diseases.