In support of this hypothesis, LAG3 was shown to selectively inhibit the activation of diabetogenic CD4+ T cells recognizing stable autoantigen–MHC class II in non-obese diabetic (NOD) mice, resulting in slower onset and lower penetrance of type 1 diabetes (T1D) than in NOD mice deficient in LAG3 (19, 36, 37). This evidence concerns the gene LAG3 and type 1 diabetes mellitus.