Reduction of HIV transmission in HIV-discordant couples wishing to conceive (2001)

In the paper by Hanabusa et al.[1] the authors claimed to be the first group to have evaluated various methods of ‘sperm washing’ to eliminate HIV proviral DNA and RNA. We disagree with a number of points in their study, and respectfully wish to point out some discrepancies. Although Hanabusa and colleagues [1] claim that theirs is the only study to have used sensitive polymerase chain reaction methods, we published a study in 1999 [2] employing equally sensitive assays including a Food and Drug Administration approved viral load assay with a detection limit of 40 HIV-RNA copies per million sperm and an in-house proviral DNA assay capable of detecting 1–10 copies of HIV DNA. Hanabusa et al. [1] also claimed that their study was the first to evaluate differential gradient only compared with gradient plus swim up when purifying or washing sperm. However, in our study [2], we stated that sperm at the interface and ‘non-swim up’ sperm did not contain detectable levels of HIV. Moreover, although Hanabusa et al. [1] quote our paper, it is completely misrepresented. On the first occasion our paper is mentioned in the discussion we are cited as Zhang et al. This is not our work, and the paper of Zhang et al. is not found in the reference list. Later in the paper, our study is quoted to show that HIV proviral DNA and RNA can be detected in sperm preparations. This most certainly was not the finding of our published study, and we would not wish to be misrepresented in such a way. After purification of the sperm we did not detect any HIV proviral DNA or RNA, and in addition did not find the expression of HIV receptors on sperm. Since setting up a sperm washing clinical service, we test all ‘washed’ sperm samples for the presence of HIV RNA by NucliSens (Organon Teknika, Cambridge, UK). To date we have tested 60 washed sperm samples and found only one to be positive by this assay. The paper by Hanabusa et al. [1] stated that the level of HIV in semen was below 105 to 107 copies/ml in other studies (including ours), thus suggesting that the initial level of HIV in semen may have been higher in their study. In fact, when the viral load was detectable in our study the levels were greater than those in the study by Hanabusa et al. [1]. Hanabusa et al. [1] concluded by stating that ‘Patients with progressing HIV infection have decreased numbers and motility of sperm and hence the risk of transmission may be higher in artificial insemination than natural conception because of multiple attempts'. However, we believe that this is not the case. An individual with a low sperm count may also embark on multiple natural attempts without knowing whether he, or his partner, are in fact fertile, possibly resulting in a much greater exposure to the virus compared with intrauterine insemination (IUI) with known numbers of HIV-tested ‘washed’ sperm. In addition, there well be more mucosal abrasion and inflammation associated with unprotected intercourse compared with IUI, again adding to the risk of HIV transmission. We have now set up a clinical service offering ‘sperm washing’ as a risk reduction programme for HIV-discordant couples wishing to have children. We believe that every possible measure must be taken to reduce the potential exposure of women to HIV. Both partners have fertility checks before they may embark on the programme, and insemination is performed in conjunction with ovulation induction. The sperm is purified by density centrifugation, washed twice followed by ‘swim up’ to remove any contaminating non-sperm cells or seminal plasma. All sperm samples are HIV-RNA tested by nucleic acid sequence-based amplification (NSBA) insemination is only performed if the result is below the limit of detection. Table 1 demonstrates the progress with our programme to date. If both fallopian tubes are blocked, in-vitro fertilization is performed using washed HIV-RNA tested sperm, and when the semen analysis is sub-optimal for either IUI or in-vitro fertilization, intracytoplasmic injection is performed. Theoretically the latter could be the safest method of reducing the risk of HIV transmission, as each oocyte is exposed to only one sperm. Further details of our protocols can found in Gilling-Smith [3].Table 1: Data from HIV ‘sperm washing’ clinical service. As the issue of whether or not sperm are infected with HIV has been controversial, and of critical importance to clinical programs advocating sperm washing, we are very encouraged to find that Hanbusa et al. [1] were able to reproduce the findings of our study. Jill W. Gilmoura Carole Gilling-Smithb Frances Gotcha