NEW YORK -- In the past two years, researchers in New York, California and at the U.S. Centers for Disease Control have seen about a dozen people who have all the symptoms of AIDS but do not appear to be infected with HIV, the virus known to cause the disease.
These findings raise the possibility that there may be a new virus, or a mutation of the human immunodeficiency virus, which cannot be detected by current tests. But researchers stress that whatever causes these cases is extremely rare.
Besides the dozen cases, a half-dozen others have been reported in the international medical literature or at scientific meetings over the same time period.
"It's clear that there are such patients. It makes sense that there could be another immonosuppressive retrovirus around. There are two [HIV-1 and HIV-2]. There could be three," said Dr. Harold Jaffe, assistant director for science of the CDC's AIDS division, studying six of the cases. "Is there a new retrovirus? We clearly don't know and I don't know if anybody does."
Dr. Jeffrey Laurence, director of the laboratory for AIDS research at Cornell Medical College in New York, said that his group had accumulated data on five patients in New York exhibiting the symptoms and that a paper on their study had been accepted for publication by a British medical journal, The Lancet.
Both Dr. Laurence and Dr. Jaffe stressed that the new cases do not mean that HIV is not the cause of acquired immune deficiency syndrome. "It doesn't change anything we're saying about what you should do to avoid getting AIDS," Dr. Laurence said. "You should still practice safe sex, and in terms of blood transfusions, we've said the blood supply is safe, but we've always said it's not 100 percent safe."