CD4(+) T cell surface CCR5 density as a determining factor of virus load in persons infected with human immunodeficiency virus type 1

The intensity of expression of the chemokine receptor CCR5 is involved in i n vitro cell infectability by human immunodeficiency virus (HIV)-1 R5 isola tes. Because CCR5 expression varies among individuals, the hypothesis that this expression could determine virus load in HIV-1-infected persons was te sted. The mean number of CCR5 molecules per cell was measured on peripheral blood CD4(+) T lymphocytes (CCR5 density) from HIV-1-infected, asymptomati c, nontreated adults. There was a strong correlation between HIV RNA plasma level and CCR5 density (P = .009) that was independent of cell activation and was not due to an HIV-induced CCR5 up-regulation, These data are compat ible with the hypothesis that CCR5 density is a key factor governing cell i nfectability and in vivo virus production and explain the protective effect of the Delta 32CCR5 deletion, which results in low CCR5 expression. CCR5 d ensity might be of critical predictive value in HIV infection.