Giant step in the long road to curing AIDS. A patient at Hospital Clínic de Barcelona has managed to absolutely control the disease without any type of treatment for more than 15 years. This is a unique case in the world, different from other cures achieved after stem cell transplantation, as with the Berlin and London patients.
What has allowed the patient to remain for so long with an undetectable viral load and without taking any medication has been her immune system. She was infected 15 years ago and, in her case, she developed the disease very quickly. In general, people take years until the virus awakens, which means they infect others without knowing it.
The affected woman, already dubbed the Barcelona patient and of whom no details have been released at her request, went to the Clínic because she felt unwell and was quickly diagnosed. She was included in a clinical trial in which she was given antiretroviral treatment for nine months and underwent various interventions with an immunosuppressant, cyclosporine A. Antiretroviral treatment, the standard for controlling AIDS, is effective in suppressing virus replication within the body and blocking transmission, but HIV persists in reservoirs and reappears after stopping therapy. Few people manage to maintain undetectable viral loads without taking medication.
When antiretroviral treatment was withdrawn in the clinical trial in which the Barcelona patient participated, the rest of the participants saw the virus multiply. The Barcelona patient was the only one to whom this did not happen and who has managed to remain so all these years. This permanent cure for AIDS occurs in a very small group of people, known as post-treatment controllers. Other cases of cure are related to bone marrow transplantation, as in the case of the Berlin and London patients, or with people who have defective viruses or genetic factors associated with a powerful immune response to HIV, known as elite controllers.
At the time, the reason for the cure of patient Barcelona was not found, but now, after monitoring her and analyzing her evolution, researchers have found it. The woman has high levels of two types of cells that have helped her naturally keep the disease at bay. "It is an exceptional case, not only because there are very few people with long-term post-treatment control, but also because of the HIV control mechanism, different from those described in other documented patients so far," says the head of the HIV group at IDIBAPS, Josep Mallolas. Researchers from Hospital Clínic-IDIBAPS, the University of Barcelona (UB), CIBERINFEC, Hospital Germans Trias i Pujol, and the Carlos III Health Institute have participated in the follow-up and study of the case.
"It is an exceptional case, not only because there are very few people with long-term post-treatment control, but also because of the HIV control mechanism, different from those described so far"Specifically, the patient Barcelona presents in abundance two types of lymphocytes: cellsnatural killer, which are part of the innate immune system and constitute the first line of defense against other pathogens, and CD8+ T lymphocytes, key agents in the defense of cells against viruses and bacteria. "The great novelty of the work is that we have characterized the cells that achieve control of the virus," says IDIBAPS HIV group researcher, Núria Climent. "The patient has very high levels of the two cells that could block the virus or destroy infected cells," adds the researcher.
The results of this exceptional case were presented this Wednesday at the AIDS 2022 World Conference. Once disclosed, the next step is to understand the mechanisms that occur in this patient and see if it is possible to replicate them in other patients. If successful, the functional cure for AIDS can be extended, meaning patients will continue to have the virus, but their immune system will absolutely control its replication. For Juan Ambrosioni, a doctor from the Hospital Clínic HIV group, achieving this type of cure is more realistic than what bone marrow transplants offer.