Beyond increasing pancreatic Treg numbers, IL-2 also directly enhances the activity of pancreatic Tregs by upregulating the expression of molecules critical for Treg function including CD25, FoxP3, CTLA-4, ICOS, and GITR (152), coupled with immunosuppression within the islets during T1D progression. Here, FOXP3 is linked to type 1 diabetes mellitus.