IFNG and autoimmune disease: Of all the known processes involving Th17 cells transdifferentiating into various effector cell types, including follicular helper T cells and regulatory T (Treg) cells, under inflammatory conditions8,9, conversion of Th17 cells into IL-17+IFN-γ+ cells (Th1-like Th17 cells) or IL-17-IFN-γ+ cells (Th1-like exTh17 cells) has been recognized as one of the major and critical pathways of Th17 cell plasticity during the development of autoimmune diseases in mice and humans2,6.