In this areas, B-T cell cross-talk is regulated by CD40-CD40L(CD154) receptors, another environment interaction known to up-regulate CCR7 expression in CLL, B-cell precursor acute lymphoblastic leukemia (BCP-ALL), or myeloid leukemia-derived DCs (74, 91–93). This evidence concerns the gene CD40LG and B-cell chronic lymphocytic leukemia.