Plasma HIV Reflects AIDS Progression
Fackelmann, K. A., Science News
Plasma HIV reflects AIDS progression
Two scientific teams reported this week that plasma and certain white blood cells from people who test positive for the AIDS virus, or HIV, harbor much more of the virus than previously suspected. The new findings, described in separate reports, suggest a tool for shortening the evaluation process in testing new AIDS drugs.
Earlier research showed that white cells called CD4-positive T4 lymphocytes carry more HIV than previously estimated (SN: 7/22/89, p.54), but scientists remained puzzled by the small amounts of HIV found in the monocytes and blood plasma of infected individuals. The new research establishes that lymphocytes, monocytes and plasma (the clear fluid remaining after all cells are removed) from HIV-positives harbor enough virus to dispel lingering doubts about HIV's central role in causing AIDS, says Mark B. Feinberg of the Whitehead Institute for Biomedical Research in Cambridge, Mass. He and Whitehead Director David Baltimore wrote an editorial accompanying the reports in the Dec. 14 NEW ENGLAND JOURNAL OF MEDICINE.
In one report, David D. Ho of the University of California, Los Angeles, and his colleagues describe their analysis of plasma, lymphocytes and monocytes taken from 54 people who tested positive for HIV antibodies. The study group included asymptomatic individuals as well as people with AIDS or ARC, an early stage of the disease. Using a newly refined, ultrasensitive culturing method, the researchers identified HIV in all 54 plasma samples and in all lymphocyte and monocyte samples. A control group of 22 healthy individuals with negative antibody tests showed no evidence of HIV in plasma or white blood cells, the team found.
"The amount of infectious HIV detected was higher by orders of magnitude than previously estimated," Ho says. Earlier, researchers had detected the virus in 1 of every 100,000 lymphocytes and monocytes taken from patients with AIDS. Ho's team found HIV in 1 of every 50,000 such cells taken from the 16 asymptomatic subjects in his group. …