The CCR5 antagonist Maraviroc (developed by Pfizer) is used as an antiviral agent in HIV infection to block viral entry into macrophages [233], whereas the CXCR4 inhibitor Plerixafor (AMD3100; developed by AnorMED and marketed by Genzyme) blocks homing of hematopoietic stem cells to the bone marrow, thereby mobilizing these cells to the bloodstream, allowing them to be collected for later transplantation [60]. This evidence concerns the gene CXCR4 and HIV infectious disease.