Because of its direct role in this pathogenic process, multiple aspects of CCR5 have been studied in the context of HIV infection and AIDS progression (Gottlieb et al., 1981; Broder and Gallo, 1984; Montagnier et al., 1984; Moore et al., 1990; Berson et al., 1996; Alkhatib, 2009). Here, CCR5 is linked to HIV infectious disease.