Subcutaneous low-dose IL-2 increases the number of circulating endogenous Tregs. (A) Treg/Tconv ratio × 100 in animals treated with IL-2+rapa and rapa alone. *P < .05, repeated-measures ANOVA. (B) Percentages (left panel) of circulating Tregs defined as a total percentage of CFSE⁺ cells (of CD3⁺CD4⁺) plus endogenous cells as gated in panel A (green) and endogenous cells as gated in panel A alone (purple). Absolute numbers (right panel) of circulating Tregs defined as an absolute number of CFSE⁺ cells (CD3⁺CD4⁺) per microliter peripheral blood plus absolute endogenous cells as calculated in panel A (green) and endogenous cells as calculated in panel B alone (purple).