CD4 and B-cell chronic lymphocytic leukemia: Further supporting the role of STAT5 activation in the increased turnover of Tcons and aTregs from CLL patients on therapy, the pSTAT5 levels in CD4+ T cells were also significantly positively correlated with the percentage of Ki-67+ Tcons, as well as with the percentage of Ki-67+ aTregs among CD4+ T cells.