CCR5 and HIV infectious disease: Chemokine receptors are used as main (CCR5) or alternative (CCR2, CCR3, CXCR4, and other) co-receptors for HIV, and it is known that some of their allelic versions may impact HIV infection (Arenzana-Seisdedos and Parmentier 2006; O’Brien and Moore 2000; Zwolińska 2009).