AIDS: treatment and transmission.

AIDS: Treatment and transmission

"It's been a tumultuous month in the AIDS fields," Martin S. Hirsch of Masscahusetts General Hospital in Boston said at the Interscience Conference on Antimicrobial Agents and Chemotherapy this week. And several presentations at the New Orleans conference relating to drug treatments and heterosexual transmission may add to the rapidly accumulating data bank, if not to the tumult.

Hirsch's comment was in response to the announcement of the expanded availability of azidothymidine (trade name AXT), an anti-AIDS drug (SN:9/27/86,p.196). Samuel Broader of the National Cancer Institute released further data on the AZT trials at the meeting, including a description of what happens to disease-fighting T4 cells during drug treatment. Viral killing of these white blood cells is blamed for the deadly immunosuppression of AIDS.

While AZT did initially boost the already-low T4 levels -- as those of placebo-treated patients continued to fall -- the average in the AZT-treated group eventually dropped to pretreatment levels, presumably through AZT's suppression of bone marrow production of T4 precursors. But Broder says the fall isn't an overwhelming concern. Only some patients showed the decrease, he says, "and even with some patients' fall, [AZT] does seem to be translating to a clinical benefit."

Broder says he's just gotten a goahead from the Food and Drug Administration to try a similar drug, dideoxycytidine, in AIDS patients. Other drugs under development were discussed at the meeting, including D-penicillamine, a compound marketed for rheumatoid arthritis and Wilson's disease, a rare metabolic disease. George Washington University researchers in Washington D.C., tried that drug in 10 patients who had the AIDS virus and perpetually swollen glands. It suppressed the virus but also temporarily depressed T cell function.

Raymond Schinazi and colleagues at Emory University in Atlanta are working on a drug similar in structure and function to AZT. Called CS-85, it is at least 7 to 10 times less toxic than AZT in bone marrow cell culture, he says.

On the transmission side, several studies reported at the meeting added to the accumulating evidence of female-to-male transmission (SN:10/5/85,p.213). While AIDS incidence in Africa and Haiti incidates that such transmission occurs, it has been difficult to document in the United States because of the relative rarity of female cases.

Brian Salzman and his colleagues at Montefiore Medical center in New York City studied 12 male partners of female AIDS patients. The men had no other risk factors for AIDS, yet six of them had antibodies to the virus, indicating that they had been exposed.

Heterosexual transmission apparently doesn't require multiple exposures to the virus: A study by the Centers for Disease Control turned up the case of a woman who developed blood signs of viral exposure after only one sexual encounter with her husband, who had picked up the virus via transfusion.