Specifically, IL21 activity led to the STAT1 and STAT3 phosphorylation, and IL4 and CD40L activity induced STAT6 and IKKα/β phosphorylation in CLL cells, respectively (Fig. 1A, B), confirming the expected biological activity of engineered HS5 cells. This evidence concerns the gene STAT3 and B-cell chronic lymphocytic leukemia.