IFNG and brain disorder: Effector T cells, i.e., T helper 1 (Th1), Th2, Th17, T regulatory (Treg), and T follicular helper (Tfh) cells as well as their signature cytokines, i.e., interferon gamma (IFNγ; TH1), interleukin 4 (IL-4; TH2) (19, 20), IL-17 (TH17) (21, 22), transforming growth factor beta (TGFβ; Treg), and IL-6 (Tfh), drive tissue inflammation in several visceral and brain diseases (23–28).