The purpose of this study was to document which genetic subtypes of HIV-2 are present in Guinea-Bissau and to investigate whether asymptomatic HIV-2 carriers and AIDS patients carry distinct genetic variants. A secondary aim was to correlate proviral DNA load to clinical and immunologic status of the patients. Thirty-eight asymptomatic HIV-2 carriers and 11 AIDS patients from Bissau, Guinea-Bissau were included in a cross-sectional study in which HIV-2 env V3 sequences, HIV-2 DNA load, and CD4-positive (CD4+) lymphocyte counts were determined. Phylogenetic analyses showed that all investigated subjects carried subtype A HIV-2 variants and that the sequences from AIDS patients and asymptomatic carriers did not form distinct subclusters in the tree. As expected, patients with AIDS had significantly higher median HIV-2 DNA load than did asymptomatic carriers (4.6 vs. 2.0 log10 HIV-2 DNA copies/10(6) CD4+ lymphocytes). Our study indicates that the HIV-2 epidemic in Guinea-Bissau is almost exclusively caused by subtype A HIV-2 variants and that the HIV-2 infections among the asymptomatic carriers and AIDS cases included in the study do not have distinct epidemiologic histories.
PIP: HIV-2 is associated with AIDS but is less pathogenic than HIV-1. HIV-2 is endemic in West Africa, with the highest prevalence in Guinea-Bissau; epidemiologic studies in the country have found HIV-2 seroprevalence in the general population to be 8-10%. HIV-2 seroprevalence increases with age and peaks near age 50-59 years, although the mean age of HIV-2-associated AIDS cases is near 40 years. Only scattered cases of HIV-2 have been reported outside of West Africa, with some concentration in Portugal, France, and India. 38 asymptomatic HIV-2 carriers and 11 AIDS patients from Bissau were included in a cross-sectional study in which HIV-2 env V3 sequences, HIV-2 DNA load, and CD4-positive lymphocyte counts were determined. Phylogenetic analyses showed that all investigated subjects carried subtype A HIV-2 variants and that the sequences from AIDS patients and asymptomatic carriers did not form distinct subclusters in the tree. Subjects with AIDS had significantly higher median HIV-2 DNA load than did asymptomatic carriers.