FOXP3 and type 2 diabetes mellitus: As shown in Fig. 1C, the levels of both Tr1 cell subsets, expressing or not Foxp3, were significantly higher in T2DM patients compared to healthy controls (median controls = 0.13, T2DM = 0.28, p = 0.015 FOXP3−; median controls = 0.26, T2DM = 0.46, p = 0.04 FOXP3 +).