In previous studies employing a NOD model, in which the spontaneous diabetes development was constrained by transgenic BDC2.5 TCR expression on all CD4+ T cells (29), acute Foxp3+ Treg cell ablation was shown to unleash a highly aggressive form of autoimmune diabetes (30), which fully abrogated the sex bias usually observed in spontaneous diabetes progression of NOD mice (31). This evidence concerns the gene FOXP3 and diabetes mellitus.