French scientists have unveiled the genetic mechanism by which they believe two m

Paris (AFP) - French scientists said Tuesday they had found the genetic mechanism by which two HIV-infected men may have experienced a "spontaneous cure", and said it offered a new strategy in the fight against AIDS. Both men were infected by the human immunodeficiency virus (HIV), one of them 30 years ago, but never developed AIDS symptoms. The AIDS-causing virus remained in their immune cells but was inactivated because its genetic code had been altered, the scientists said. The change appeared to be linked to increased activity of a common enzyme named APOBEC, they theorised. The "apparent spontaneous cure" throws up an intriguing avenue for drug engineers, the team said in a statement. "The work opens up therapeutic avenues for a cure, using or stimulating this enzyme, and avenues for identifying individuals among newly-infected patients who have a chance of a spontaneous cure." The work, published in the journal Clinical Microbiology and Infection, was carried out by scientists at France's Institute of Health and Medical Research (Inserm). HIV replicates by invading human CD4 immune cells, which it reprogrammes to become virus factories. A rare group of people -- fewer than one percent of those infected -- are naturally able to rein in viral replication and keep the virus at clinically undetectable levels. They are known as "elite controllers", but the mechanism by which they keep the virus at bay remains a mystery. The French group looked at two such individuals, a 57-year-old man diagnosed HIV-positive in 1985, and a 23-year-old diagnosed in 2011, and sequenced their virus genomes. Though they remained infected, standard tests could not detect the virus in their blood. The team found that in both cases, the virus was unable to replicate in immune cells due to mutations in its genetic code. The researchers suggested spontaneous evolution between humans and the virus, a process called "endogenisation" that is believed to have neutralised other viruses in humans in the past. READ MORE