Researchers find another piece to the AIDS puzzle

AIDS researchers announced Thursday that they had finally cracked a long-standing puzzle: Why a few people can get infected with the AIDS virus and remain healthy without treatment.

It was the culmination of a 16-year effort that started with one HIV-positive minister coming into the office of AIDS researcher Bruce Walker and asking to become a human guinea pig.

Episcopal minister Robert Massie was expected to have died from his infection years earlier, and yet felt inexplicably well. He thought if doctors studied him, they might find a way to help others with HIV to stay healthy, too.

Eventually, thousands of HIV-positive volunteers joined the effort, including about 20 in Philadelphia, helping scientists to pinpoint a set of genetic differences that allow about 1 in 300 infected people to keep the virus in check.

Thanks to their genetics, these "controllers" have a slightly different immune response - a better ability to signal danger so that "killer" T-cells can keep the AIDS virus from replicating and destroying immune cells.

The researchers hope their findings, released Thursday afternoon in the online version of the journal Science, could help inform the quest for new AIDS therapies. About 33 million people worldwide are infected with the virus, including about 19,000 in Philadelphia, which has one of the nation's highest infection rates.

Luis Montaner, an immunology professor at Philadelphia's Wistar Institute, called the work "a very significant and Herculean" achievement. Montaner is engaged in a related project, trying to prompt patients' immune systems to control the virus even when they are not gifted with controller genes.

Massie said he discovered he was HIV-positive in 1984, the same year he was married. He was 26 years old. Since childhood, he had been treated for the genetic blood disorder hemophilia, which required him to get frequent blood transfusions. His HIV infection was traced to a transfusion in 1978, which meant he had been living with the virus for more than five years.

Doctors at the time told him five years was about as long as anyone had carried the virus before getting deathly ill with AIDS. After he'd had HIV for 10 years, that became the new outer limit.

"I always had a sense I was kind of staring right off the cliff," Massie said.