Phenotypic patterns of HIV-1 clonal populations during highly active antiretroviral therapy (HAART)

Several studies have demonstrated that during HIV-1 infection many differen t viral clones may co-exist in the same individual. These clones may differ regarding their biological phenotype and may influence both the natural hi story of infection and the clinical response to antiretroviral therapy. The aim of the present study was to investigate the influences of combinati on therapies including protease inhibitors (HAART) on the phenotypical patt ern of HIV-1 biological clones in peripheral blood mononuclear cells. Viral isolation and biological characterisation of bulk isolates and clonal vira l isolates were performed on two AIDS patients, before and after three mont hs of antiretroviral therapy. A decrease of viral load in plasma specimens in association with a change o f clonal composition during antiretroviral therapy was observed in both pat ients during treatment. Before therapy both of the patients had a syncytium inducing (SI) bulk isolate and the majority of the biological clones were characterised as SI. After treatment, the bulk isolates were still SI in bo th cases, but the majority of biological clones were characterised as non-s yncytium inducing (NSI). These results suggest that HIV clonal composition and relative phenotypic p attern undergo different changes not only during the natural course of HIV infection but also while patients are on antiretroviral combination therapy .