Two cases of probable cure of HIV are known worldwide. But the consortium IciStem, of which the Institut Pasteur is a partner, has just detected a third, in Germany. This is the “Dusseldorf patient”, a man who has been HIV positive since 2008, treated with an antiretroviral. In 2010, he was diagnosed with leukemia, first treated with chemotherapy, before a relapse in 2013. There, a bone marrow transplant was planned, and doctors try to kill two birds with one stone: what if we treated HIV and leukemia at the same time ? The results of this study are published on February 20 in the journal NatureMedicine.
They are betting that a certain type of donor – very rare – could offer this patient a chance to cure HIV at the same time as the blood cancer for which he is being treated. For this, this donor would have to carries a genetic mutation known to protect against HIV, CCR5 delta-32, i.e. 1% of the population. The challenge is great, especially since the donor must also be immunogenically compatible so that the transplant is not rejected.
The donor meeting these two conditions is found (which is a feat), the patient from Düsseldorf is transplanted and followed closely, and at the same time cured of his leukemia. In 2018, doctors no longer detect HIV and therefore propose to stop antiretroviral treatment by monitoring it closely, to see if the virus is still present or not. After 44 months of study, they come to the conclusion that he is no longer HIV positive and is therefore probably cured.
How did this transplant work?
“The HIV virus is known to target 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.“, underlines one of the co-authors of the study. It would therefore seem that the transplant process has “emptied” the viral reservoir. the donor’s immunity to HIV would have been passed on to the sick patient preventing what was left of the virus from spreading.
Why do we speak of “probable cure” and not of absolute cure? Because “nWe were unable to analyze all of the patient’s tissues to formally rule out the presence of HIV in the body.“, specify the researchers. That said, “these results indicate that the immune system did not detect the virus after treatment was discontinued“.
Source :
- NatureMedicineFebruary 20, 2023
- Press release – HIV: third case of probable cure in the world after a bone marrow transplant, Institut Pasteur