Researchers have identified the second HIV patient to apparently clear the virus from her body—without the use of antiviral drugs.
According to Monday’s report, Annals of Internal MedicineA 31-year old woman was first diagnosed with HIV in 2013. She only received antiretroviral treatment for six months while pregnant to stop the transmission of the virus to her child. Yet multiple sophisticated tests looking for genetic evidence of HIV in the patient’s blood showed no intact virus in her cells, says Dr. Xu Yu, who led the research team reporting on the case. She’s a principal investigator at the Ragon Institute of Massachusetts General Hospital, MIT and Harvard, as well as an associate professor of medicine at Harvard Medical School. The findings suggest that the patient’s immune system was even able to clear the reservoirs of HIV that allow the virus to continue replicating for decades. Current anti-HIV drugs can lower virus levels to undetectable levels but can’t completely rid the body of these lingering reservoirs of the virus.
“There is no way to ever say we have proof that there is not a single virus in this patient,” says Yu. “The only thing we can say is that after analyzing a large number of cells from the patient, with the technology in our lab we cannot reject the hypothesis that the patient probably reached a sterilizing cure by natural immunity.”
There have been previous reports of patients who stopped taking anti-HIV medications and achieved undetectable virus levels for years, including Timothy Ray Brown, who’s also known as “the Berlin patient,” and Adam Castillejo, “the London patient.” Both, however, had been diagnosed with cancer and benefited from having a stem cell transplant to treat it, which replaced their immune cells with ones from donors that included cells that could block HIV infection. The patient Yu describes also had latent HIV reservoirs.
She is only the second woman to appear to have been cured of the virus. Yu’s team described the first person, known as “the San Francisco patient,” in 2020. This second patient, who’s from Esperanza, Argentina, is working with Yu’s team and continues to provide blood samples for ongoing research studies. She is currently pregnant with her second child, and Yu and the patient’s doctors are discussing whether her remarkable, apparently virus-free condition means she won’t need to take anti-HIV drugs before and during delivery (which guidelines currently recommend for pregnant women who are HIV positive). For scientists to determine whether the breast milk contains virus, the Esperanza patient will provide samples.
Yu’s team has analyzed 1.5 billion blood and tissue cells from the Esperanza patient since 2017, searching for any hints of whole genetic virus material that would indicate a virus that could potentially still be active and replicate again. However, they were unable to locate such evidence. But they did discover fragments of HIV gene DNA that suggested this patient may have been HIV-positive at one time. Similar clues were found in the San Francisco patient.
Yu warns that these findings might not apply to all HIV patients. The elite controllers are people who can suppress HIV with low levels and sometimes undetectable levels without anti-HIV medication. Researchers around the world are studying these people intensively; it’s not clear what percentage of those infected with the virus are able to naturally contain it with their immune systems, but Yu believes that the two patients she described suggest that there may be more. She’s hoping that hearing about the first two will encourage others to get tested and studied, so scientists can better understand what aspect of their immune systems are providing such an effective way to block HIV.
“Many immune factors could be playing a role,” she says. “Now that we have a second case, there are probably many cases out there that may not know they have a sterilizing cure. Others may not know they are infected. The goal is to get more patients. If there are a few of these very rare cases we will be able to study their immune reactions more thoroughly and possibly give clues about the factors that contribute to this condition. Then we can apply what we learn to the general population.”
Since the first elite controllers were identified among sex workers in Africa in the 1990s, scientists have been studying their immune systems, looking at everything from the antibodies they make to the immune system’s highway made up of lymphocytes. So far, they haven’t identified what is keeping these people protected from severe disease, but Yu says more sophisticated ways of searching for even the slightest hint of HIV’s genes are making it possible to find people like the San Francisco and Esperanza patients. It could also help to move the research on elite controllers. Yu hopes to compare, for instance, the immune responses of these patients with those who take anti-HIV medications. It’s possible that the drug cocktails produce an immune response weaker than what’s generated by these two patients, and scientists could find ways to bolster that response.