All other cytokines caused non-significant increases of CLL B-cell survival: the percentages of viable cells were 32.2%±21% in complete medium (control), and 37.8%±27.8%, 29.6%±18.6%, 29.4%±18.2%, 30.2%±17.2%, 33.8%±23.8%, 33.2%±23.3%, and 29.4%±18% in the presence of IL-2, IL-6, IL-10, IL-12, IL-15, IL-21 and APRIL, respectively. This evidence concerns the gene IL21 and B-cell chronic lymphocytic leukemia.