Abstract

To assess the correlation between HIV-1 RNA load in blood and semen by antiretroviral therapy status and the relative penetration of antiretroviral drugs in seminal plasma. We performed a cross-sectional cohort study of 119 HIV-1 subjects divided into three groups according to treatment status. Blood and semen were collected concurrently. Seminal viral load determined by NucliSens® HIV-1 QT PCR (BioMerieux). Viral suppression over time was assessed in a second semen sample collected from 10 treated subjects. Antietroviral plasma concentrations were measured by high performance liquid chromatography and recovery experiments were performed on semen samples to validate quantitation in this matrix. All subjects taking non nucleoside reverse transcriptase inhibitors (n = 36, mean treatment 33 months ± 14) or protease inhibitors (n = 45, mean treatment 31 months ± 25) had blood viral load < 50 copies/mL and seminal viral load < 250 copies/mL. In untreated subjects (n = 38), blood and semen viral loads were positively correlated (Spearmans p = 0.489, p = 0.002). Blood and semen nevirapine concentrations were positively correlated (r2 = 0.795, p = 0.005) and therapeutic concentrations achieved in both compartments. Lopinavir and atazanavir also penetrated semen but efavirenz did not. We find that there is compartmentalisation of HIV-1 within the male genital tract and propose that new infections may originate from untreated men and that suppressive antiretroviral regimens may reduce the risk of sexual transmission.

Keywords: Antiretroviral therapy, HIV-1, semen, sexual transmission, viral load