CCR5 and HIV infectious disease: Because CCR5 is critical in HIV infection and transmission, as observed with CCR5-Δ32 homozygous cells resistant to HIV infection [84], the manipulation of CCR5 expression on HIV target cells has been intensively investigated and is considered to be effective [34,35,37,39,40,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102].