In contrast, ex vivo mitogen stimulation of PBMCs using phorbol 12-myristate-13-acetate (PMA)/ionomycin led to higher percentages of interferon (IFN)γ-expressing Th1-like T-cells in CLL patients compared with HC [16, 17], which is in line with data from the TCL1 AT mouse model [17]. This evidence concerns the gene IFNG and B-cell chronic lymphocytic leukemia.