AIDS TREATMENT UPDATE, Issue 37, January 1996
Raffi Babakhanian

HIV-positive men have the added dilemma of not wanting to infect an HIV-negative partner. Two teams of researchers have been working on a technique to 'process' the sperm of HIV-positive men in order to reduce or even eliminate the risk that it may infect an HIV-negative female partner. This procedure is called sperm washing.

HIV IN SEMEN

Semen is a mixture of sperm cells and seminal fluid. Studies suggest that HIV is not present in the sperm themselves but rather in the fluid which surrounds them. The idea behind sperm washing is to separate the sperm from the fluid. 'Washing' the sperm is only one of the three methods that are used. First the semen is centrifuged to separate most of the fluid from the sperm. Then the sperm is washed in a solution to remove more fluid and to kill any HIV that is clinging to the outside of the sperm cells. These two steps are repeated at least twice. The washed sperm is tested by PCR to ensure that no HIV is detectable, then combined with an artificial semen solution and inseminated into the woman.

Since 1989 researchers at the KIS-Curatorium for Immunedeficiency in Munich and the Department of Obstetrics and Gynaecology at the University of Milan have been inseminating 'washed' sperm in couples where the man is HIV-positive and the woman is negative. As of September 1995, 621 inseminations had been carried out on 215 women. 54 children had been born and another 55 women were pregnant. So far no mothers or children have tested HIV-positive. 159 women have been pre-screened and are awaiting insemination.

While these results are encouraging, they do not definitively show that sperm washing provides any protection against HIV over unprotected sex. That's because the risk of infection in a single act of unprotected heterosexual sex is very low; although there is no firm evidence, it is thought to be at most 1 in 200 and probably very much lower. The fact that no woman has become infected with HIV through 'washed' sperm may just be chance.

Since this is not a blinded clinical trial of this technique, it will require several thousand inseminations before it is known if sperm washing reduces the risk of HIV transmission. Some researchers argue that a formal trial should be conducted, in case the procedure actually increases the risk of transmission by removing anti-HIV antibodies from the semen, or by causing physical trauma during the insemination. At this time, researchers are advising couples that the procedure is not proven and is best used by couples who would otherwise have engaged in unprotected sex in order to have a child.

Separately, researchers at Harvard Medical School in the USA have reported that the sperm of men with CD4 counts of 200 or less is less able to impregnate than the sperm of asymptomatic or HIV-negative men. The researchers looked at ejaculate volume, sperm concentration and the ability of the sperm to swim properly to assess the 'fitness' of the sperm. However, they did find that men with advanced HIV disease who were taking AZT had nearly normal sperm. It is not known whether other anti-retroviral drugs also improve the 'fitness' of the sperm.

While it is too early to say whether sperm washing will prove to be a completely safe method of insemination, it provides an alternative for couples who would otherwise resort to unprotected sex. Currently there are no studies of sperm washing in the UK.

9601
ATU3702

Copyright © 1996 - AIDS Treatment Update. Permission granted for noncommercial reproduction, provided that our address and phone number are included if more than short quotations are used. Subscription lists are kept confidential. NAM Publications 16a Clapham Common Southside, London, England SW4 7AB; TEL: 01-71-627-3200 (from outside the UK: +44-171-627-3200); FAX: 01-71-627-3101 (from outside the UK: +44=171-627-3101)  info@nam.org.uk  http://www.nam.org.uk