The untreated recovery of an HIV-positive patient offers hope and leads to new insights. This almost unprecedented discovery may help in the development of a vaccine and what is known about the mechanisms that may be at the origin of this very special case.
A solution to cure HIV may come from the patient named Esperanza. A young woman from Argentina who tested HIV-positive in 2013 has been cured of the virus without treatment, say researchers from the University of Buenos Aires, Harvard and MIT, in a study published on November 16th in the journal Annals of Internal Medicine.
They explain that this anonymous patient no longer carries any trace of HIV in her body. She only received treatment for a few months in 2017, during a pregnancy.
So far, only one case of natural recovery has been reported, that of a 67-year-old woman in San Francisco in 2020.
The authors of this new study hope that their patient's immune system will help to better understand how to fight the virus that causes AIDS, which is now known to be contained but not eliminated.
The study is extremely serious with all the teams involved being leading teams in this field. They had just published an article in the journal Nature on what are known as “elite controllers”, patients who control the virus (without being cured) spontaneously without any treatment. They are known, they represent about 0.5% of the population. The researchers wanted to study the amount of HIV virus in the bodies of these patients. This is how they noticed this woman, in whom they were unable to detect the presence of the virus in 1.1 billion cells. In patients who control the infection, the virus is still found. In her, absolutely nothing. The analysis they did on this patient is simply impressive.
Do we know how this spontaneous recovery could be explained?
In the "elite controllers", these patients who spontaneously manage to control the infection, the researchers see a very strong immune response from CD8 T lymphocytes (another type of white blood cell), which we don't see in other patients. About 50% of them carry a gene that also promotes their immune response.
Does this, under certain conditions, eliminate any trace of virus capable of reproducing?
One can imagine. Perhaps as soon as a cell containing replication-competent virus starts to produce even a little bit of it, it will be killed. It is also possible that in this patient, the virus reservoir cells have a fairly short lifespan. In any case, if researchers were able to carry out work on this scale on all the elite controllers, they would find other cases of spontaneous recovery. They would remain rare, but they would make it possible to build up a cohort of patients that we could follow to understand what happened.
How can the study of these very special cases help HIV research?
Researchers will have to understand this cure, but it gives them hope. They know that contact with HIV does not provide protection. You can be reinfected, superinfected... In order to find a vaccine against this virus, they need to teach the immune system to do what it cannot do naturally when it encounters HIV. Understanding how this happened in this patient is bound to have an impact on the strategies to be followed in designing a vaccine. And advances in HIV research are providing knowledge that will be used against other viruses: without them, we would not have had a vaccine against Sars-CoV-2 so quickly.