A TINY WIN AGAINST AIDS?

By MICHAEL D. LEMONICK

The AIDS epidemic has been in full swing for more than a decade now, but despite huge investments of research money and intellectual capital, medical science still has no effective weapon against the disease--and no definite idea of what such a weapon would even look like. Under these demoralizing conditions, any scrap of progress, no matter how tenuous, triggers an enormous surge of hope. It happened again last week with a report in the New England Journal of Medicine: doctors at UCLA announced that a five-year-old boy, infected with HIV at birth, has been symptom-free ever since. More important, over the past four years the scientists have not been able to detect even a trace of HIV in the child's system.

If they're right, this is by far the most convincing of a handful of cases in which the human immune system has apparently defeated the otherwise invincible AIDS virus. And by understanding just how the boy's biochemical defenses achieved such an upset, doctors speculate, they may someday find a way to protect the rest of us.

Even as the news was being trumpeted, however, some AIDS experts were sounding notes of caution. Nobody denies that the boy, whose identity is being kept confidential, is healthy, or that the most exquisitely sensitive tests in existence can't find any HIV in his body. The question is whether he was ever actually infected.

Drs. Yvonne Bryson and Irvin Chen, who led the UCLA study, are convinced he was. His mother was HIV-positive when she gave birth, and blood tests at 19 and 51 days showed that the baby carried the virus too. But when the researchers retested the child at 11 months of age, the virus was gone. That seemed so wildly improbable that the scientists conducted more tests and still found nothing. When they re-analyzed blood from the earlier tests, though, the virus was still there. Could the samples have somehow become tainted with HIV in the testing lab? Such contamination has been suspected in other cases in which infections have disappeared. But no, the virus from both samples was genetically identical, making the contamination notion highly unlikely.

So why is there any doubt? For one thing, the UCLA researchers can't explain how the child could have fought off the virus, especially since a baby's immune systems isn't fully functional until the age of 18 months or so. Moreover, the HIV in the baby's and the mother's blood is genetically different. That could be, as the UCLA researchers assert, because the mother's virus wasn't studied until a year after the birth, and had time to mutate. Even if the baby did pick up HIV from his mother, that doesn't mean he was infected. Immunologists know that living cells from mothers often get passed along to newborns, where the cells generally die within a few months. And, says Dr. Max Essex, chairman of the Harvard AIDS Institute, "it hasn't been rigorously proven that the infection was in the infant's own cells."

Bryson and Chen admit this possibility, but consider it unlikely; in fact, they are looking into a second, similar case. If they're right, says a skeptical Dr. Jeffrey Laurence, chief of the AIDS research lab at New York Hospital-Cornell Medical Center, "it would be extraordinarily important, if only to give us a psychological boost, showing that we can, potentially, find a fully protective vaccine." And if they're wrong, it will hardly be the first time in the course of this devastating plague that hopes have been briefly raised, only to crash once more.

--Reported by Jeanne McDowell/Los Angeles and Lawrence Mondi/New York

With reporting by JEANNE MCDOWELL/LOS ANGELES AND LAWRENCE MONDI/NEW YORK