FOXP3 and type 1 diabetes mellitus: Type 1 diabetes features a lifelong Treg cell defect; namely, by an increase in resting Tregs (rTregs, or CD4 + CD25 + Foxp3 + CD45RO) and a paucity of activated Tregs (aTregs, or CD4 + CD25 + Foxp3 + CD45RA) compared to nondiabetic controls.