A bone marrow transplant in a treated HIV-positive person has significantly reduced the reservoir of the HIV virus and achieved prolonged remission without treatment.
In an HIV-positive patient treated, an allogeneic stem cell transplant for acute lymphoblastic leukemia can considerably reduce the size of the reservoir of the AIDS virus, according to a new study published in PLoS Medicine.
The virus has become undetectable using the most sensitive current techniques (PCR, culture, in situ hybridization, etc.) and the researchers have wondered about stopping the anti-retroviral treatment.
No curative treatment currently
Around 36 million people worldwide are living with HIV, which remains controlled at a low level in the blood with antiretrovirals, but no curative treatment currently exists: as soon as the antiretroviral treatment is stopped, the viral load traced back.
A study, carried out at the University of Melbourne in Australia, shows that allogeneic transplantation is capable of reducing very deeply and in a prolonged manner the size of the reservoir of the HIV virus, even below the detection limits of current techniques. New hope for research.
A prolonged disappearance of the virus
In their study, the researchers collected blood and tissue samples (colon, etc.) before and after allogeneic stem cell transplantation in an HIV-positive person treated with antiretrovirals. At the same time, they measured the size of the HIV reservoir.
They found that this decreased considerably after the transplant and that they were unable to detect the virus with all the tests available.
Following this observation, the antiretroviral treatment was stopped on the 784th day after transplantation. The patient experienced complete remission without treatment for 288 days, then a rebound in viral load was observed, which led to a resumption of antiretroviral therapy on day 5 of the rebound.
The sequencing of the virus observed during the rebound remained very close to that of the initial virus.
New tools to continue research
For the time being, scientists do not have the tools necessary to precisely measure the size of the residual reservoir of the HIV virus after allogeneic stem cell transplantation. They cannot therefore say that there will be a cure or not and choose an appropriate complementary treatment.
Only one case in the world of a person cured of AIDS has so far been described. This is the American Timothy Brown, also known as the “Berlin patient”. He was diagnosed with HIV in 1995 and has shown no signs of infection since 2007. Doctors have managed to treat him by performing bone marrow transplants from people with mutant immune cells that are naturally resistant to the AIDS virus. A natural immunity which is endowed with 0.3% of the world population.
In-depth research could thus make it possible to find, in the long term, a treatment to completely cure HIV-positive people.
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