A small French study of 14 HIV patients who have remained healthy for years after stopping drug treatment offers fresh evidence that early medical intervention may lead to a "functional cure" for AIDS, researchers said.
The research, published in the US journal PLoS Pathogens, comes on the heels of a report last week that a baby in Mississippi appeared to be cured of HIV after aggressive antiretroviral drug treatment delivered within 30 hours of birth.
Experts agree that while parallels between the two studies are intriguing, the phenomenon is rare -- and warn that most of the 34 million people infected with HIV worldwide would develop full-blown AIDS if they stopped taking drugs to repress the human immunodeficiency virus.
Myron Cohen, a well-known US expert on HIV and chief of the Center for Infectious Diseases at the University of North Carolina, described the French study as "provocative."
"It provokes us to think. Who in the universe of people treated early can come off treatment? They showed us some clues, but it is a question that demands more science," he told AFP.
The study involves 14 adults, a group known as the VISCONTI cohort, which stands for Viro-Immunologic Sustained Control After Treatment Interruption.
They were treated for HIV with a range of antiretroviral drugs, each within 10 weeks of infection, and stopped treatment around three years afterward on average.
The group has been able to keep viral loads under control for a median of 7.5 years without drug treatment, said the study.
The individuals do not have the genetic characteristics of another rare group of people - fewer than one per cent of the population - who appear able to spontaneously stave off HIV without medicine and are known as "natural" or "elite controllers."
Those in the VISCONTI group, described as "post-treatment controllers," have not completely eliminated HIV from their bodies. They continue to maintain it at a low level in their cells and have not become sick.
Researchers cautioned, though, that the mechanism that explains why these patients can fight HIV without drugs remains unclear. Several immunologic tests have not found a singular cause for their continued control of the virus.
"These individuals reflect what a functional cure may represent because they have been actually controlling the infection for many years now," said lead researcher Asier Saez-Cirion of the Institut Pasteur in Paris.
"I think this is proof of concept that this may be achieved in individuals," he said in a phone interview with AFP. "And that this happened thanks to early treatment onset." All of those in the study live in France and currently range in age from 34 to 66.
They were infected with HIV in the 1990s and 2000s. Since they were handpicked for the study after they appeared to be able to control HIV upon stopping treatment, it is unclear what percentage of the population they may represent.
Preliminary research on them was presented at the International AIDS Conference in Washington last year. Scientists are continuing to study the group for clues about how and why their bodies act the way they do.
After an acute infection, HIV establishes viral reservoirs in cells that allow it to hide and return, even after prolonged treatment, meaning that most patients who stop taking medication see the infection return.
"These reservoirs are what stand between us and a cure for HIV," said Rowena Johnston, amfAR (The Foundation for AIDS Research) vice president for research.
"The control of HIV infection even after therapy is stopped is an interesting phenomenon that hints at what antiretroviral therapy might be able to achieve over and above its use as ongoing treatment," she told AFP.
According to Christine Rouzioux, who is part of the French research team, the early treatment "may have limited the establishment of viral reservoirs" and helped to preserve the patients' immune responses.