Expression of BCL-2 and PD-1 in CD4Tregs in pediatric and adult patients. (A) BCL-2 mean fluorescence intensity (MFI) in CM CD4Tregs at baseline (W0) and at weeks 2, 4, and 8 of IL-2 therapy. (B) Percentage of CM CD4Tregs with PD-1 expression. Box plots depict the 75th percentile, median, and 25th percentile values; whiskers represent maximum and minimum values, except for outliers. Blue, pediatric cohort. Red, adult cohort. The number of patients evaluated at each time point is indicated at the bottom. *P < .05, **P < .005 pediatric vs adult, Wilcoxon rank-sum test.