It is possible that the IL-4, IL-10, and tumor necrosis factor-α cytokine profile of ZAP-70+ CD4 lymphocytes might favor B-CLL cell growth and survival and, in contrast, the IFN-γ and IL-2 profile in CD4 lymphocytes from ZAP-70- B-CLL patients might promote an antitumor cytotoxic CD8+ T lymphocyte and NK cell response (29). The gene discussed is IL4; the disease is B-cell chronic lymphocytic leukemia.