Consistently, some data by our group and others indicated that IFN-γ secreted by CD8+ T cells inhibits the transition of Th1 cell into Th2 cells, and thus decreased M2 macrophage polarization and macrophage-to-myofibroblast transition or monocyte-to-fibroblast transition, subsequently attenuating the extent of renal fibrosis (Figure 2) [11,13]. The gene discussed is IFNG; the disease is renal fibrosis.