CXCR4 and B-cell chronic lymphocytic leukemia: From this perspective, the inhibitors of chemokines or their receptors, alone or in combinatorial protocols, might contribute to directly and/or indirectly counteracting B cell clone expansion, as well as their crosstalk with microenvironmental cells, as demonstrated with the anti-CXCR4 mo-Ab ulocuplumab in CLL/stromal cells co-cultured in vitro [48].