(AFP) - French scientists said Tuesday they had found the genetic mechanism by which two HIV-infected men may have undergone a spontaneous "cure," and said it offered a new strategy to fight AIDS.
Both men were infected with the human immunodeficiency virus (HIV), one of them for 30 years, but never developed symptoms of AIDS.
The virus that caused AIDS remained in its immune cells but was inactivated because its genetic code had been altered, the scientists said.
The change seemed to be linked to the increased activity of a common enzyme called APOBEC, they theorized.
The "apparent spontaneous cure" raises an intriguing avenue for drug engineering, the team said in a statement.
"The work opens avenues for a therapeutic cure, using or stimulating this enzyme, and avenues for identifying individuals among new infected who have a chance for spontaneous healing."
The work published in the journal Clinical Microbiology and Infection, was conducted by scientists at the Institm of France's Institute of Health and Medical Research.
HIV replicates by invading human CD4 immune cells, which are reprogrammed to become virus factories.
A rare group of people - less than one percent of those infected - are naturally able to control viral replication and keep the virus at undetectable levels.
They are known as "elite controllers," but the mechanism by which they keep the virus under control remains a mystery.
The French group observed such individuals, a man of 57 years diagnosed HIV positive in 1985, and a man of 23 years diagnosed in 2011, and the genomes of its viruses were sequenced.
Although they remain infected, standard tests could not detect the virus in their blood.
The team found that in both cases the virus was not able to replicate in immune cells due to mutations in its genetic code.
The researchers suggest spontaneous evolution between humans and viruses, a process called "endogenization" that is believed to have neutralized other viruses in humans in the past.
A similar process has been witnessed in a population of koalas who integrated an AIDS virus into their genes, neutralizing it, and were passing resistance to their offspring.
"We propose that curing HIV can occur through HIV endogenization in humans," the team wrote.
"These findings suggest that without prophylactic and therapeutic strategies, after several decades of HIV / host integrations, and millions of deaths, it is likely that some individuals may have endogenized and neutralized the virus and transmitted to their offspring, they add.
"We believe that the persistence of HIV DNA can lead to healing and protection, from AIDS."
The approach taken so far has been the opposite: to try and erase all traces of HIV from human cells and from cellular reservoirs where they hide.
"We suggest that the persistence of HIV DNA is not integrated as a barrier, but rather, it may constitute a precondition for HIV cures," said the study authors.
"We propose a new vision of HIV cures through the integration, inactivation and potential endogenization of a viral genome in the human genome."
- Not exclusive -
The team said they do not believe that two patients were the only ones to develop this process or that the phenomenon is new.
And they called for a "huge" sequencing of human DNA, particularly from Africans who had been exposed to HIV to obtain the longest possible stage of endogenization, in order to find yet another proof.
There is only one person who has been literally cured of HIV: Timothy Ray Brown who had bone marrow transplants as a treatment for leukemia from an HIV-resistant donor. Editor's note: All attempts to repeat the act have resulted in death in the post operative period
A baby who was given anti-AIDS drugs immediately after birth with follow-up up to eighteen months, led scientists around the world to believe the girl, the Mississippi baby would have been cured, but the virus later destroyed that hope too.
For those who want to know more about placental (Opens in another tab)
Translated from the original in English Scientists see mechanism for spontaneous HIV 'cure' by Cláudio Souza.
Reviewed by Mara Macedo
Created by: Brigitte Castelnau