This suggests that IL-10 production by TH17 cells in the gut is also regulated by Maf. The reduction of IL-10 expression not only by TH17 cells, but also Treg, could explain colitis onset observed only in mice where all the T cells are inactivated for Maf. Furthermore, we observed an increased percentage in IFNγ+TH17 cells while the percentage of IL-17A+ TH17 cells remained similar in MafΔTcells mice compared to Maff/f or MafΔTreg mice (Fig. 6F). The gene discussed is MAFF; the disease is colitis.