CCR5 and HIV-1 infection: Other variables need to be characterized, such as the natural ligands of CCR5 RANTES and the macrophage inflammatory protein 1α (MIP-1 α) [10,102]; immune response genes—the human leukocyte antigen (HLA) and NK cell immunoglobulin-like receptor [50,103,104], β-defensin [105], and Toll-like receptors [106]; and the profile of expressed cytokines [47,49,55], which play a suppressive role in HIV-1 replication and affect the natural history of HIV-1 infection.