DETECTION AND BIOLOGIC CHARACTERIZATION OF INFECTIOUS HIV-1 IN SEMEN OF SEROPOSITIVE MEN

Objective: Factors that influence the infectivity of an individual and the impact of antiviral treatment on infectivity are not well defined . This study investigated the value of a sensitive method for detectin g infectious HIV in semen for use as a marker for infectivity. Design: A cross-sectional study of infectious HIV in the semen of 33 HIV-posi tive men. Methods: A sensitive method for detecting infectious HIV in semen was used. The correlation of culture in semen with clinical and laboratory data was investigated. Biological phenotypes of isolates fr om blood and semen were tested using an MT-2 assay. Results: HIV cultu res from seminal cells were positive in 18 patients (55%) and in one p atient from seminal plasma. Higher recovery rates of HIV from semen co rrelated with a low CD4 count (80% in patients with a CD4 count > 100 x 10(6)/l versus 33% In patients with a CD4 count < 100 x 10(6) cells; P < 0.025) and symptomatic disease (78 versus 27% in asymptomatic pat ients; P < 0.01). Recovery of HIV from semen was independent of presen ce or absence of plasma viremia and the biological phenotype of blood isolates. Ten patients with syncytium-inducing (SI) isolates in their blood had positive semen cultures for HIV. Seven of the 10 patients ha d SI isolates recovered from their semen, whereas three had non-SI iso lates only. Conclusion: Data from partner studies show higher rates of HIV transmission for patients with low CD4 counts and symptomatic dis ease. The compatibility of epidemiologic data with our finding that si gnificantly more HIV is recovered in semen from patients with advanced disease, suggests that HIV culture of semen samples may provide a use ful surrogate marker to measure infectivity in clinical studies. Furth er studies are needed to define the inoculum required to transmit HIV and to study the impact of sexually transmitted diseases and HIV-1 phe notype on semen infectivity.