Receiving an HIV diagnosis several decades ago was practically a death sentence for many patients who saw that there was no possible treatment to eradicate this virus and that sooner or later would develop the disease. But little by little, treatments for prophylaxisof attenuation, reaching an undetectable viral load, and now we are seeing the first cases of complete eradication.
There are several cases. We are facing a new historical milestone in medicine, and it is no wonder, since an international consortium of researchers has documented the tenth case in the world of a person who has managed to be cured of HIV, or rather, who has managed to eliminate the virus from their body so as not to develop the disease.
The latter is known as the ‘Oslo patient’. A 62-year-old man who has not taken antiretroviral treatment for four years and has no trace of the virus, which has led to a published article in Nature where a great research process is recounted, something that has been possible thanks to the work of the international consortium IciStem 2.0, led by the Oslo University Hospital and with a fundamental participation of Spanish science through the center IrsiCaixa.
His story. The clinical history of the ‘Oslo patient’ follows a pattern that is increasingly familiar to scientists, similar to that of the famous ‘Berlin patient’ in 2009. Diagnosed with HIV at the age of 44, the patient developed severe hematological cancer in 2020, for which he had to receive a stem cell transplant with the aim of regaining normal blood cell genesis.
But here the key to success was that the donor of these stem cells was his own brother, who had a rare and coveted genetic alteration known as the CCR5-delta32 mutation.
Because. When we see the term ‘mutation’ we automatically go to the negative meaning and all the diseases that having a mutation in the DNA can cause. But the reality here is that the CCR5-delta32 mutation acts as a cellular “shield” by modifying the receptors of a type of defense cell, T lymphocytes, so that HIV be unable to anchor to them and infect them causing its destruction.
In this way, by replacing the patient’s immune system with his brother’s cells, doctors not only treated the cancer, but “rebooted” their defenses, making them immune to the virus. From here, HIV could not access its defensive cells, which is the mechanism it uses to become chronic and become ‘undetectable’ to the immune system.
What happened next? As the researchers report, two years after performing the transplant, the medical team decided to withdraw antiretroviral therapy under strict monitoring, since it is a truly critical moment for patients. From here, and several analyzes later, it was seen that there was no sign that the virus was multiplying again.
In the end, viral DNA was not detected either in peripheral blood tests or in biopsies of intestinal tissue, which usually acts as a “reservoir” where the virus hides. And this is where the Spanish group, through IrsiCaixa, has had a lot to say, since its research teams are currently monitoring 40 participants in similar conditions.
What does it mean? Although it seems that we have achieved the definitive cure, the reality is that this is not the case. Right now we must understand that hematopoietic stem cell transplantation is a very high-risk and extremely clinically aggressive procedure that initially leaves the patient without any defenses and then they trust that the transplant will work and they will not reject it.
All of this makes its mortality rate very high, so it is only ethically and medically justified in patients suffering from a potentially fatal blood cancer, not as a standard therapy for people living with HIV, who today can lead a normal and healthy life thanks to daily antiretroviral treatments.
It’s the way. Although it is not the definitive therapy, it does open the way to developing genetic therapies such as CRISPR or cellular treatments such as therapies CAR-T that manage to imitate this immunity in the patient’s own body in a safe, scalable way and without the need to undergo a transplant from an external donor. Although to get here there is still a long way to go for science.
Images | National Institute of Allergy
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