(Montreal) From the very first days of infection, HIV constitutes “reservoirs” where it will hide, preventing triple therapies from completely eradicating it, a Montreal research team has demonstrated for the first time.
This discovery makes it possible to better understand when and how the virus constitutes these reservoirs which ensure its survival.
The team of researcher Nicholas Chomont, from the CHUM Research Center, revealed that a small fraction of the virus integrates into the genome of CD4+ T lymphocytes during the acute phase of the infection, i.e. from the first weeks .
The virus does not replicate inside these lymphocytes, which are nevertheless responsible for activating the human body’s defense against infections, which allows it to escape detection.
This is the first time that this phenomenon has been measured in humans. It had so far only been seen in animal models of the disease.
This discovery, Chomont said, is important “to try to understand how we can try to block this phenomenon”.
“If we better identify the cells that HIV infects at the very beginning, this could lead to the development of treatments to limit the spread of the virus, that is to say, to further improve triple therapies by making them more effective from the start. start,” said Mr. Chomont. And then it can also help us better understand how these reservoirs are established and therefore prevent their establishment. »
The researchers found that during the first seven days of infection, the number of CD4+ T cells affected by the virus increased from 10 to 1000 cells per million CD4+ T cells, which testifies to the extremely rapid spread of HIV.
Scientists have known for some time that cells of the immune system are the primary target of HIV. However, these cells are not all identical, and this is where their work held surprises for them.
Cells called follicle cells, which are found in the lymph nodes and are a major contributor to HIV replication, were until now thought to be among the earliest targets of the virus.
“It’s not that at all,” explained Mr. Chomont. These cells appear after the infection, and after that the virus infects them. But at the very beginning of the infection, these are not the cells in which it will replicate. »
The triple therapies currently available, he adds, are so effective that they can destroy 99.9% of the virus in the body, to the point where the life expectancy of people infected with HIV is practically identical to that healthy people.
These reservoirs where the virus hides while waiting for it to be given the chance to come back are truly the last obstacle that remains to be overcome in order to defeat the disease, whether by going to attack and destroy the virus in its hiding place, or even by l simply preventing you from going to hide somewhere at the start of the infection.
“The goal of tritherapies is not to prevent the virus from falling asleep, it is to prevent it from replicating,” said Mr. Chomont.
Some currently available molecules could prevent the virus from going into hiding, but they would have to be administered from the start of the infection to measure their effectiveness. This obviously implies very rapid screening of new patients, which is really “a political and financial question”, said the researcher.
In the meantime, there are many glimmers of hope for HIV patients. In addition to the work done by M. Chomont and others, the scientific literature recently testified to a third patient who was “cured” of his infection after a bone marrow transplant.
If such an intervention is simply not possible to treat everyone, we also know that two women got rid of the virus on their own, recalled Mr. Chomont.
“It opens up really interesting new avenues of research because we didn’t think the body was able to get rid of it on its own,” he said.
The findings of this study were published by the medical journal Immunity.