Although CXCL12 has been previously linked to T-cell immune suppression in cancer (47) and even to IL-10 production in T cells (48, 49) and tissue-infiltrating B cells (50), this is the first report to investigate an immunomodulatory function of CXCL12 in CLL and propose an underlying mechanism for IL-10 production by CXCL12. Here, IL10 is linked to B-cell chronic lymphocytic leukemia.