CXCR4 and B-cell chronic lymphocytic leukemia: Given the critical role of CXCR4-CXCL12 axis in migration of CLL cells between blood and supportive lymphoid tissues in CLL, the formation of CXCR3-CXCR4 heterodimers on CLL cells and its consequences may significantly reduce the migration of CLL cells [1, 21, 22].