CD4 and B-cell chronic lymphocytic leukemia: The percentage of aTreg subsets, defined as either CD45RA−FOXP3hi or CD45RA−CD25hi CD127lo/− cells (Supplementary Figure S2B) among CD4+ T cells was significantly positively correlated with the lymphocyte count (Figure 1E), suggesting that this specific subset is associated with a malignant B cell burden in patients with CLL.