New HIV patient cure not applicable on a large scale

A fourth case of cure of HIV infection was announced this Wednesday (27). Despite the good news in the midst of the disease pandemic, experts say the way in which remission was achieved is not a large-scale applicable public health strategy.

The 66-year-old, who declined to reveal his identity, is the fourth patient said to be cured of HIV. He was nicknamed the “City of Hope patient”, citing the City of Hope health facility in Duarte, California, where the man was treated.

The patient is now 17 months without signs of the virus in the body, even with the stop in treatment with antiretrovirals. The use of the drugs could have been stopped even earlier, according to the health center, but they waited until the moment he was vaccinated against Covid.

The remission of the infection in man occurred due to the treatment of a second disease. Because of leukemia — a cancer that affects blood cells — the patient had to undergo a bone marrow transplant, where blood cells are produced.

With the transplant on the horizon, doctors then looked for a bone marrow donor who was naturally immune to the HIV virus. In this case, it was a genetic search for a donor with a rare mutation in the CCR5 gene.

This gene produces a protein that, in general, allows HIV to enter human CD4+ defense cells. People who have received a particular CCR5 mutation from both their father and mother—that is, are homozygous for that mutation—are resistant to infection with some of the variants of HIV.

The transplant took place about three and a half years ago. From this, the patient from City of Hope was able to block the way for HIV to enter his defense cells and, in this way, he was cured.

The same process was used in 2007 for the first cured case of HIV infection, Berlin patient Timothy Ray Brown.

Now, however, he is the longest-lived HIV patient (31 years of infection) to achieve remission after a bone marrow transplant. The City of Hope health center also points out that the patient treated there is the oldest person to be cured, due to the transplant, both from HIV infection and from cancer. At the time of the procedure, the man was 63 years old.

Cases like this, however, should not be seen as a feasible possibility for large-scale treatment.

“In the case of transplantation, the bone marrow donor was lucky enough to have the mutation and the recipient was compatible”, says Aguinaldo Roberto Pinto, professor in the department of microbiology, immunology and parasitology at UFSC (Federal University of Santa Catarina).

Pinto has been conducting research in the area of ​​immunobiology and molecular epidemiology of HIV for years. For him, news of healing like this is very positive, but it is necessary to have certain reservations.

“We do not believe that this will have an impact on most people. Firstly, because in order to have a bone marrow transplant, you have to be in a clinical situation in which you need [da doação]”, he says. The fact that this was the fourth documented remission since 2007 shows how rare a cure is, he adds.

The professor explains that it is already difficult to find a compatible donor for the patient who needs a bone marrow transplant. Thus, finding someone who would need to have the mutation that confers natural resistance to HIV would be one more difficulty in the donation process.

“This is not going to be recommended for everyone”, he summarizes.

Alexandre Grangeiro, former director of the national HIV/AIDS program and a scientific researcher at the USP School of Medicine, also points out that the cure in these cases is much more related to “a conjunction of chance than to an intentionality”.

He explains that a medical discovery needs some requirements to become a health strategy applicable to a considerable contingent of people. One is that the possible harms of the intervention do not outweigh the benefits. In the case of bone marrow transplantation, this balance could be more doubtful due to the risks that the action brings to the patient.

For example, there are cases of transplant where something called “graft-versus-host disease” occurs. It consists of the attack on the transplanted’s organs by the donor’s bone marrow cells.

Even so, Grangeiro points out that the news of the patient’s cure is encouraging. “This fourth case consolidates evidence that had already proved to be quite correct regarding the possibility of a cure through bone marrow transplants.”

The researcher also indicates that the new case of remission is a demonstration that the cure of the infection is something closer since the first case of HIV, about 40 years ago.

“The cure for HIV today has been treated as something possible and that it may not take so long. It is all very uncertain, but there is a certain optimism”, he says.