FOXP3 and type 1 diabetes mellitus: Although we found no evidence for differential IFN-γ production in T1D patients compared to healthy controls among HELIOS− CD45RA−CD127lowCD25lowFOXP3+ cells, on a per cell basis (Supplementary Fig. 7B), the higher frequency of the CD25lowFOXP3+ subset among patients resulted in a significant increase in the frequency of circulating FOXP3+ cells with the capability to produce IFN-γ following stimulation among total CD4+ T cells (P = 2.5 × 10−3; Supplementary Fig. 7C).