Evaluation of sperm washing as a potential method of reducing HIV transmission in HIV-discordant couples wishing to have children

Objective: A number of discordant couples, in whom the man is HIV positive and the woman is HIV negative, wish to have children. To conceive they must abandon protected sex, posing a risk of HIV transmission to the woman and so to the child. In such circumstances purification of spermatozoa ('sperm- washing') to inseminate the woman artificially has been proposed as a metho d of reducing the risk of transmission. Here we evaluate whether this does represent a true risk reduction. Methods: Semen samples from HIV-positive patients were separated into sperm atozoa, non-sperm cells (NSCs) and plasma fractions. The amount of viral RN A present in each fraction was measured and compared with the level in the peripheral blood. Each fraction was also assessed for the presence of provi ral DNA. The ability of spermatozoa to be infected was assessed by evaluati ng for the presence of HIV receptors, i.e. CD4, CCR5 and CXCR4 on the surfa ce of the sperm, by flow cytometry. Results: A poor correlation was Found between the levels of HIV in blood an d semen. Within the semen the virus was restricted to the plasma and/or NSC s. All spermatozoa were negative for viral RNA or provirai DNA. Spermatozoa did not express significant levels of CD4, CCR5 or CXCR4, suggesting that they are unlikely to be major targets for HIV infection. Conclusions: These data suggest that spermatozoa are not major targets of H IV infection. Purifying spermatozoa reduced the level of HIV RNA and provir ai DNA to below the detection limit of the assays irrespective of the amoun t of virus present in the unfractionated semen. On the basis of these data we would recommend 'sperm-washing' followed by insemination as a safer alte rnative to natural conception for HIV-discordant couples wishing to have ch ildren. (C) 1999 Lippincott Williams & Wilkins.