While the basal phosphorylation of STAT5 was significantly increased in CD4+ T cells from patients on CIT and was positively correlated with both proliferating Tcon and aTreg subsets, basal pSTAT5 levels were also significantly higher in aTregs compared to Tcons from treated patients with CLL. The gene discussed is CD4; the disease is B-cell chronic lymphocytic leukemia.