Thus, the downregulation of CXCR4 and TACI induced by differentiation of CLL B-cells may deprive the cells of survival mediators including the TACI ligands BAFF and APRIL and the CXCR4 ligand CXCL12 [48, 57]. The gene discussed is CXCR4; the disease is B-cell chronic lymphocytic leukemia.