French scientists have reported finding a genetic mechanism by which they believe two men were spontaneously cured of HIV, a breakthrough that could lead to a new approach in the fight against AIDS.

Scientists at Institute of Health and Medical Research in Paris tested 1,700 people diagnosed as HIV-positive, then focused their research on two men.

One was diagnosed HIV-positive in 1985, but never suffered any illness linked to the HIV infection, despite being continuously exposed to the virus through syringes he shared with his HIV-positive wife.

The other man was diagnose HIV-positive in 2011, but has never been ill and the virus cannot now be detected with routine blood tests.

"HIV from the two studied patients was inactivated by interruptions in their genes," said researcher Philippe Colson. "HIV is still present but is no more able to replicate."

The scientists believe the virus was deactivated by the combined effect of a common enzyme and a viral protein, resulting in spontaneous changes to the men's DNA.

Despite still being HIV-positive, the genetic changes gave the men protection from the virus.

The researchers said genetic changes of this nature are not unusual in both humans and other mammals, especially when provoked by a retrovirus like HIV.
 
"We believe that the persistence of HIV DNA can lead to cure, and protection from HIV," Colson and co-author Didier Raoult wrote in the journal Clinical Microbiology and Infection.

Purging HIV DNA

The team believe the same response could be induced in other HIV-positive patients. "Strategies to imitate the phenomenon observed in these patients may be implemented," said Colson.
 
If successful, the approach would be very different from most other efforts to cure people of the virus. These aim to purge all the HIV DNA from the cells of patients, rather than finding a way to deactivate them.
 
"Previous and current researches are important. We hypothesise that there may be another way," says Colson.
 
But turning their findings into an effective treatment will take years, and is by no means assured.
 
"Ultimately this is an observation," said Dr Rowena Johnston, Director of Research at amfAR, the Foundation for AIDS Research. "And it's always difficult to turn an observation into an intervention."
 
The researchers said they intend to study similar patients, in an effort to confirm and better understand the extent of the phenomenon.
 
"There is potential for these kinds of cases to inform our efforts to cure HIV," said Johnston.

"But it's a challenge that researchers all over the world have been working on for a long time, without any one answer seeming to characterise all those cases, let alone any ideas on how to make this a reality for 35 million people living with HIV."

Source: Al Jazeera