HIV-1 in semen: determination of proviral and viral titres compared to blood, and quantification of semen leukocyte populations.

Abstract

This study was carried out to determine the relationship between proviral DNA and viral RNA titres in semen compared with blood. In addition, the association between semen leukocyte counts with detection frequency and absolute levels of human immunodeficiency virus type 1 (HIV-1) nucleic acids was also assessed. Paired samples of blood and semen were collected from a cohort of individuals with different blood CD4 cell counts, and whose anti-HIV therapy had not changed in the preceding 3 months. The cell-associated proviral DNA titres and cell-free plasma viral RNA titres were determined using nested primer polymerase chain reaction and NASBAtrade mark, respectively. In addition, leukocyte counts were determined by immunocytochemical and cytochemical staining of a subset of semen samples. HIV-1 proviral DNA was detected in 100% and 47%, and viral RNA was detected in 76% and 63%, of blood and semen samples tested, respectively. HIV-1 proviral DNA and viral RNA titres in blood were higher than in corresponding semen samples, although the difference observed in viral RNA titres was not statistically significant. Proviral DNA and viral RNA titres were correlated between the two body fluids, and within the semen, although some individuals had disparate semen and blood titres or detection rates, indicating genital tract compartmentalisation. In addition, detection of HIV-1 proviral DNA, but not of HIV RNA, in semen was associated with elevated semen leukocyte counts, although this latter finding requires verification in future studies of larger numbers of patients.