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A woman from Esperanza, Argentina appears to have been "naturally" cured of human immunodeficiency virus (HIV). 

This is the second documented case of its kind in the world. Both rare cases were identified by a research team led by Xu Yu, MD, a member of The Ragon Institute of Massachusetts General Hospital, MIT, and Harvard. 

Lian Xiaodong, a member of Yu's team, said to National Business Daily (NBD) that the identification of the "Esperanza Patient" is of great significance, as it suggests the possibility that other people with HIV may have also rid themselves of the virus. 

Findings suggest there is a specific killer T cell response that could be responsible for keeping the virus suppressed without the need for medication, medical experts said to NBD. 

"Natural" cure of the deadly virus

In August 2020, Yu's research team identified one HIV patient from San Francisco who had no intact HIV viral sequence in her genome, indicating that her immune system may have eliminated the HIV reservoir. This is the first known incidence of a "sterilizing cure" without a stem cell transplant. 

Yu and her colleagues have been studying the HIV reservoirs of "elite controllers", who have immune systems that are able to suppress HIV without the need for medication.

Recently, her team reported a second untreated HIV-infected patient, known as the "Esperanza Patient". Tests on more than a billion of her cells found no viable trace of the infection.

The new finding may represent a second instance of a "sterilizing cure". 

"One possibility for what happened is that the two patients both had an immune response that was able to very effectively target a vulnerable part of the virus, and that these cells were produced very rapidly during the initial infection," Steven Deeks, Professor of Medicine in Residence at the University of California, San Francisco (UCSF), explained to NBD. "Should this happen, the virus could in theory be controlled before it had a chance to spread throughout the body."

Dr. Natalia Laufer, the medical doctor of the "Esperanza Patient" and HIV researcher at Universidad de Buenos Aires, echoed Dr. Deeks' viewpoints when reached by NBD. "Our findings suggest there is a specific killer T cell response, mainly killer T cell (also called cytotoxic T cell) that could be responsible for keeping the virus suppressed without the need for medication." 

The discoveries of Yu's team suggest there might be more HIV-infected people with the possibility of eliminating the virus on their own, and give the whole world hope that it may be possible someday to find a way to cure more people of the virus.

"These findings, especially with the identification of a second case, indicate there may be an actionable path to a sterilizing cure for people who are not able to do this on their own," said Dr. Yu. "We are now looking toward the possibility of inducing this kind of immunity in persons on ART (Antiretroviral Therapy) through vaccination, with the goal of educating their immune systems to be able to control the virus without ART."

Next, Yu's team will work harder to identify more cases with such possibility and compare them with other HIV-infected people requiring ART treatment to suppress the virus so as to pinpoint the underlying immune mechanism, Lian Xiaodong said to NBD.

Effective cure for HIV seems to be less elusive

Approximately 38 million people around the world are currently living with HIV. And there is still no effective cure yet. 

So far, only two have been cured of the virus with medical treatment, and receiving stem cell transplants from donors carrying a rare genetic mutation called CCR5-delta 32 made them resistant to HIV. 

But the method used in both cases is not appropriate for all patients, commented Ravindra Gupta, a researcher at the Division of Infection and Immunity at the University College London (UCL). More importantly, the transplant is expensive and risky and it is also extremely hard to find appropriate donors.

However, it does offer new hope for HIV patients and the potential of adding new treatment strategies.

Currently, HIV is primarily treated with ART, which could suppress viral replication but couldn't eliminate the viral reservoir that can produce more HIV virus. Research finds that one in 200 people with HIV can control the virus without medication, and they are the so-called "elite controllers". 

Lian Xiaodong told NBD that "elite controllers" also have killer T cell responses, but more research will be needed to explain why the "San Francisco Patient" and "Esperanza Patient" could eradicate the HIV virus on their own. "The research team is now working on the specific characteristic of the two rare cases from the perspective of broadly neutralizing antibodies, but hasn't got any results yet," Lian added. 

"If, as many expect, killer T cells were responsible for this potential cure, then vaccines designed specifically to produce such cells can be produced and tested. Indeed, the field is already working on such vaccines, often leveraging the work being done in producing COVID vaccines," Dr. Deeks remarked. 

In August 2021, biotech company Moderna announced the plan to start the Phase I trials of its experimental HIV vaccine that uses the mRNA technology, the same technology that underpins its Covid-19 vaccines. 

Dozens of healthy adults without HIV were enrolled to test the safety of the vaccine and basic immune response. The trials are expected to end in the spring of 2023.

Email: lansuying@nbd.com.cn