The frequency of both T helper 1 and 2 (TH1 and TH2) CD4+ T cells is increased in CLL, and, although there is no clear TH1/TH2 skewing, TH2 expansion correlates with progressive disease, in line with their proposed tumor-supportive role in CLL [19,20]. Here, CD4 is linked to B-cell chronic lymphocytic leukemia.