Active HIV-1 redistribution and replication in the brain with HIV encephalitis

The central nervous system (CNS) is of particular importance in human immun odeficiency virus type 1 (HIV-1) infection. First, the CNS may be difficult to access for anti-retroviral treatment and may become a sanctuary for res idual viruses. Second, HIV-1 infection may lead to AIDS dementia complex (A DC) culminating in HIV-1 encephalitis. In order to examine the pattern of d rug resistance and the role of encephalitis in enhancing viral redistributi on to the CNS, we compared pol gene quasispecies of the spleen and brain in two patients with and two patients without HIV-1 encephalitis, who had bee n treated with zidovudine (AZT). Although a variable degree of AZT resistan ce was noted in both the spleen and brain of all patients, phylogenetic ana lysis indicated that quasispecies developed rather independently in the sys temic circulation (spleen) and CNS (brain) of patients without HIV-1 enceph alitis, while similar pol gene sequences were obtained from the two compart ments of patients with HIV-1 encephalitis. env gene V3 region of patients w ith HIV-1 encephalitis showed distinct quasispecies in the spleen and brain . Our results suggest that HIV-1 redistribution to CNS is more active in ca ses with encephalitis and that HIV-1 distributed late to CNS grow actively under certain selective pressure exerted on the V3 region of the env gene.