The baffling case of an AIDS-like malady.

Reports presented at the VIII International Conference on AIDS last week raised the possibility that an unidentified virus causes an AIDS-like illness in some people. Now, a California researcher says he has found hints of such a virus in one woman who is afflicted with this mysterious syndrome.

The U.S. Centers for Disease Control (CDC) in Atlanta previously had identified six cases of the strange illness; doctors attending the AIDS conference in Amsterdam described others, bringing the total to several dozen cases, says CDC's Harold W. Jaffe. Like people with AIDS, those with the mystery illness show signs of a damaged immune system and develop opportunistic infections such as Pneumocystis carinii pneumonia. However, they all test negative for HIV-1 and HIV-2, the two viruses known to cause AIDS.

The anecdotal accounts of an AIDS-like syndrome that surfaced at the Amsterdam conference prompted the early release of research findings by Sudhir Gupta, chief of immunology at the University of California, Irvine, and his colleagues. Gupta's team studied a 66-year-old woman with sharp declines in her CD4 T-lymphocytes, a type of white blood cell targeted by HIV-1 and HIV-2. This woman showed no sign of either virus but suffered from P. carinii pneumonia. The research report will appear in the Aug. 15 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES.

To unravel the puzzling case, the researchers first drew blood from the woman and isolated white cells of various types. Next, they took healthy white cells from other sources and added them to white cells taken from the patient. In analyzing the fluid surrounding the cells, they discovered evidence that a virus infecting the patient's white cells had infected the added cells. The researchers call the virus "human intracisternal retrovirus."

Gupta and his colleagues found evidence of the same virus in the woman's 38-year-old daughter, who has an abnormally functioning immune system but shows no symptoms of pneumonia or other opportunistic infections.

The data suggest an association between human intracisternal retrovirus and the older woman's illness, Gupta told SCIENCE NEWS. However, the scientists don't have proof that this virus caused her illness or that of patients identified by other research teams. Establishing a cause-and-effect relationship will require a lot more work, Gupta says.

The 66-year-old woman received a blood transfusion a few years before her daughter was born, raising the possibility that the virus spreads through exposure to tainted blood, he says. However, "I don't think there's any reason for concern at this stage about the safety of the blood supply," Gupta says, noting that the US. blood supply is carefully screened for HIV-1 and HIV-2.

Other U.S. research laboratories have been studying cases of the baffling AIDS-like syndrome. One such inquiry, at the Aaron Diamond AIDS Research Center in New York City, has turned up hints of an unidentified retrovirus in two of the four cases studied so far, says John Moore, an AIDS investigator at the center. The scientists don't know whether that retrovirus will match the one uncovered by Gupta's team.

For now, the scientific story about this illness is characterized by a spate of questions and very few answers. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases in Bethesda, Md., points out that the preliminary reports of viral involvement may turn out to be false leads, perhaps caused by contamination of cell cultures or some other glitch.

"We're left with these hints that a virus is involved," Fauci says. At this point in time, we really can't make any definitive statements'

Scientists don't really know whether the AIDS-like illness is caused by one virus, several viruses, or any infectious agent at all, Jaffe adds. The unidentified immune deficiency might represent a rare malady that has existed for a long time, yet received very little attention until AIDS researchers started focusing on the immune system, he points out.