BARCELONA, Spain- A patient has been controlling HIV for 15 years without any type of medication, an exceptional case of functional cure for AIDS that is being studied in Barcelona (northeastern Spain) to open new avenues of research, aimed at trying to replicate the mechanisms immune systems of this woman in other infected.
This case, which is being presented at the AIDS Congress in Montreal (Canada) this week, is different from the known ones with patients from Berlin and London who achieved a complete cure because the virus disappeared after a stem cell transplant to treat the hematological diseases that they suffered.
In the case of the already baptized “Barcelona patient”, it is a functional cure, since the woman still has the virus, but her immune system can completely control replication fifteen years after having stopped treatment for AIDS , according to the Hospital ClÃnic de Barcelona, in charge of the study.
More than fifteen years ago, the patient was diagnosed in the stage of acute HIV infection —the earliest— and was included in a clinical trial with antiretroviral treatment for nine months and various interventions with an immunosuppressant, cyclosporine A.
How do HIV treatments work?
Antiretroviral treatment, the standard for controlling AIDS, is effective in suppressing viral replication within the body and blocking transmission to others, leaving the patient with such a low blood level of HIV that it becomes undetectable in a conventional analysis.
But HIV persists in reservoirs, so if therapy is stopped, it has the ability to replicate and can attack the patient again.
However, a very small group of people, such as “the patient from Barcelona”, are “post-treatment controllers” and, after stopping the medication, manage to maintain undetectable viral loads.
Other cases of cure are related to bone marrow transplantation -Berlin and London- or to exceptional cases that have defective viruses or genetic factors associated with a strong immune response to HIV from a type of lymphocyte, patients who are known by the name of “elite controllers”.
Why is the case of the “Barcelona patient” so important?
The head of the HIV unit at the Hospital ClÃnic, Josep Mallolas, highlights that the Barcelona case “is exceptional not only because there are very few people with long-term post-treatment control (15 years), but also because of the HIV control mechanism, different from that described in ‘elite controller’ patients and other cases documented so far.
In this sense, “the patient from Barcelona” does not have classic genetic factors associated with the control of the disease or defective virus, since the researchers isolated samples in the laboratory and verified that her HIV had the conditions to replicate.
The researchers also confirmed that their T-lymphocytes – key agents of the immune system – are susceptible to HIV infection, suggesting that other cell populations in the blood were blocking infection and could contribute to disease control.
What is new is that the researchers have characterized the two populations of cells that manage to control HIV: the “natural killer” (NK) cells, which are part of the innate immune system and constitute the first line of defense against different pathogens, and the CD8+ T lymphocytes, which play a key role in defending cells against viruses and bacteria.
“Compared to other people, the patient has very high levels of these two populations that may be blocking the virus and destroying infected cells,” said researcher Núria Climent.
From now on, the objective is to decipher in full detail the success model of this patient’s immune system, of which no details have been revealed at the express request of the patient, to determine if it is possible to replicate it in other affected patients, which It would be a giant step in controlling the great pandemic of the second half of the 20th century.
