A small, select group of people infected with HIV showed extraordinary immune responses that were able to hold the virus in check after early and aggressive treatment.
Researchers in France have closely followed 14 patients who were treated within 10 weeks of infection with combination antiretroviral drugs (cART) for three years on average and then stopped therapy.
"Our results show that early and prolonged cART may allow some individuals with a rather unfavourable background to achieve long-term infection control and may have important implications in the search for a functional HIV cure," Asier Sáez-Cirión of Institut Pasteur in Paris and his co-authors concluded in this week's issue of the journal PLoS Pathogens, published by the Public Library of Science.
Those who are functionally cured still have residual virus that is not completely eliminated but it doesn't seem to impact their well-being.
The French researchers found no signs of sickness or growth of the virus in the patients, who are known as the Visconti cohort.
They suspect that the very early treatment may have limited the chance for viral reservoirs to form, which is why the vast majority of people infected with HIV need to continue treatment.
The 14 patients are the exception to the rule. In most people who are diagnosed with HIV, the infection is detected years after it first appears.
The French team estimated up to 15 per cent of people with HIV may be functionally cured.
Normally, when drug treatment is stopped, the virus rebounds and "bad things happen," said Dr. Julio Montaner, director of the BC Centre for Excellence in HIV/AIDS at St. Paul's Hospital at the University of British Columbia.
"If diagnosed with HIV, the best course of action …to actually prevent morbidity and mortality and similarly to prevent transmission is to engage in treatment at the earliest possible time and stay on treatment for the duration until we know better," Montaner advised.
The findings don't offer any immediate clues that could be translated into care for patients, Montaner said. But they do open the door to looking for laboratory assessment tools towards that goal.
The 14 patients' "extraordinarily strong immune responses" to HIV offered a sense of optimism for Dr. Mark Wainberg, director of the McGill University AIDS Centre at the Montreal Jewish General Hospital.
"So that teaches us that maybe if we could find a way to strengthen the immune response against HIV in everybody we might be better able to deal with this illness," Wainberg said.
The findings come two weeks after researchers described an anecdotal case of a baby girl in Missiissippi. In her case, the virus may have spontaneously cleared, said Wainberg. He called comparing the French adults to the U.S. baby an apples and oranges difference.
For example, the risk of mother-to-child transmission of HIV can be reduced to less than five per cent through a combination of measures, according to UNICEF.
Timothy Ray Brown, also known as the "Berlin Patient," is thought to have been cured of HIV after receiving a bone marrow transplant as treatment for leukemia. Researchers have found traces of HIV in his tissue but the virus can't replicate.