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Forty years after the discovery of the virus responsible for AIDS, the Institut Pasteur announces a case of probable cure, the third to date in the world. It would follow a bone marrow transplant.
According to the latest figures, 38.4 million people worldwide are living with HIV. With only 2 cases of “cure” described so far: a patient from Berlin in 2009 and a patient from London in 2019. On February 20, the IciStem consortium, of which the Asier Sáez-Cirión team is a part, he Institut Pasteur, in collaboration with the University Hospital of Düsseldorf announces great news: a new probable case of HIV recovery in a man followed in Düsseldorf. A detailed case today in NatureMedicine.
The double effect of a treatment against leukemia
The study thus details the course of this patient n°3. In 2008, a medical team from Düsseldorf diagnosed a patient with an HIV infection. According to the recommendations at the time, in 2010 the patient began antiretroviral treatment, which allowed him to control the infection and reduce the amount of virus to undetectable levels in the blood. The man continues his treatment, but in 2011, he is also diagnosed with leukemia, that is to say a cancer of the cells of the immune system located in the bone marrow. He then receives chemotherapy, which allows him to control the leukemia, but does not prevent him from relapsing. A transplant of stem cells from an anonymous donor is planned for 2013. Initially, a donor whose immunogenetic characteristics are compatible with the patient is sought. Then, in these unique cases of people living with HIV, a donor carrying the CCR5 delta-32 mutation is sought. Indeed, this genetic mutation is known to prevent the entry of HIV into cells and therefore protect against infection.
“We know that the HIV virus targets the cells of the immune system. During a bone marrow transplant, the patient’s immune cells are thus completely replaced by those of the donor, which makes it possible to eliminate the vast majority of infected cells. explains Asier Sáez-Cirión, head of the Viral Reservoirs and Immune Control Unit at the Institut Pasteur, and co-lead author of the study.
But the medical act presents a challenge in itself: less than 1% of the general population carries this protective mutation. So finding it in a donor is an exception.
No more trace of virus in the patient treated to date
More than 5 years after the transplant, and after going through various complications, the patient is stabilizing. In 2018, the medical team, which no longer detected the presence of the virus, decided to stop antiretroviral treatment against HIV with supervision. The patient remains followed for 44 months, without any trace of viral particle or activatable viral reservoir in the patient’s blood or tissues being detected. No activation of the immune responses characteristic of HIV infection is detected either. “Although we could not analyze all of the patient’s tissues to definitively rule out the presence of HIV in the organism, these results indicate that the immune system did not detect the virus after the interruption of treatment.”, comments Asier Sáez-Cirión.
Data that allows the scientific team to say that this person is probably cured of HIV infection.
What are the other cases of HIV remission in the world?
The Pasteur Institute explains that some people are able to maintain an undetectable viral load for long periods in the absence of antiretroviral treatment, which is recognized as remission of HIV infection. “The case of people who have received a bone marrow transplant goes beyond this situation of control” says Asier Sáez-Cirión.
To date, only two other similar clinical cases, that of New York and that of City of Hope Hospital (Duarte, USA), have been presented at scientific conferences in 2022 after a 12-month follow-up without viral rebound. following discontinuation of antiretroviral therapy. “None of these people have special immune characteristics that would allow them to spontaneously control HIV infection. The virus was eliminated from their organism following a medical intervention for another pathology” states the press release.
However, stem cell transplantation only applies to people suffering from a hematological disease and for whom no other therapeutic alternative exists. In the case of people living with HIV, antiretroviral treatment is currently the best therapeutic alternative.
The search for a cure continues
If the stem cell transplant is not a solution for all people with HIV, research continues, strong of 40 years of discoveries. Contacted by Doctissimo about this third case of recovery, Asier Sáez-Cirión confirms that it allows us to open up new horizons
“This is an exceptional case, which is not transposable to all people living with HIV, but there is starting to be a repetition with a therapeutic procedure, a proof of concept” rejoices the seeker
How can this influence the rest of the research? The scientist evokes several avenues that emerge from these identified cures:
“On the one hand, there is research that stems directly from these cures, and which studies how to introduce this CCR5 delta-32 mutation through a process of gene therapy on people living with HIV, without going through bone marrow transplantation. . On the other hand, the 3 cases of cure confirm the usefulness of a double component: the bone marrow transplant which reduces the viral reservoir by replacing the immune system and the introduction of this barrier (the mutation) which will prevent the multiplication of the virus in the body. It is on this idea of a double component that we continue to work to develop new strategies”
All of this work focuses more than ever on two priority issues: how to eliminate the viral reservoir in people with HIV and how to develop an effective preventive vaccine against the virus.