Researchers in Massachusetts say they have discovered another patient who appears to have completely defeated HIV infection without the help of antiviral treatments or a bone marrow transplant. The case of patient Esperanza, as the woman is now called, suggests that more people can naturally cure a viral infection than is currently thought, according to the authors. Also offers more hope that a similar cure can be found for the vast majority of patients who have been burdened with HIV all their lives.
Members of the Ragon Institute – a medical institute focused on HIV research, with scientists from Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University – have been studying a group of HIV patients for years. These patients are known as “elite controllers” and all appear to have an immune system that can effectively keep HIV under control without antiretroviral therapy (ART), the standard course of treatment.
For most infected people, ART is needed to prevent the virus from replicating en masse within certain immune cells, which ultimately destroys the immune system and causes a condition known as AIDS. While ART can lower HIV levels so low that a person is no longer contagious to others, the virus can still hide inside some cells and avoid complete eradication. Usually, if a person stops taking ART (or if the virus develops sufficient resistance to drugs), the virus can come out of this reservoir and cause devastation again. Elite controllers, on the other hand, do not seem to need treatment at all, keeping their HIV viral load low on their own.
The group is in August 2020 published their latest research on elite controllers. One of these patients not only controlled the infection herself, they claimed, but completely eradicated it. The group was unable to find any traces of the virus in more than a billion blood cells taken from this patient, even using the latest genetic tests.
There were other patients documented that they completely or practically defeated HIV. These patients are traditionally given a nickname to preserve their anonymity, which usually corresponds to their location, such as a patient from Berlin. Two patients they are known to have been completely free of HIV – known as a sterilization drug – after undergoing a bone marrow transplant. Bone marrow transplants effectively replace a person’s immune system with a donor immune system, and both patients received bone marrow from people with a rare genetic mutation that is thought to make them much less vulnerable to HIV infection. Although successful, bone marrow transplants are too dangerous and cumbersome to ever become a major cure for HIV. There have been other cases of people having persistently low HIV levels after they stopped taking ART.
But the patient of the San Francisco group is unique even among these cases because she has never undergone any treatment. At the time, researchers speculated that this patient may not be the only one among their elite controllers. And they seemed to be right. In a new study published On Monday, the Annals of Internal Medicine now claim to have documented another such patient, whom they called the Esperanza patient. As before, the group failed to find any amount of virus in over 2 billion blood and tissue cells collected from the woman.
“The examples of these two cases really suggest that our current efforts to find a cure for HIV infection are not elusive. If we learn how natural immunity to the virus works, we will be able to do it, ”study author Xu Yu, a researcher at the Ragon Institute, told Gizmod by phone.
There are still many puzzles to be solved regarding these cases. A San Francisco patient first contracted HIV in 1992 and for a long time studied as an elite controller, but it is not known when her infection went from restraint to overcoming. The Esperanza patient, on the other hand, lived with HIV for about seven years before Yu’s group declared her cured, increasing the chance that a natural victory over the virus may not take so many years for those blessed with the ability to do so. . The group believes there are more naturally healed people out there, unaware of their happiness.
Of course, the most important question is how the immune system of these two people performed this trick. Yu’s group and others suspect that certain immune cells programmed to kill other immune cells that have kidnapped germs like HIV play a key role, but more than one mechanism is likely to be involved. Some of the group’s elite controllers also appear to be functionally cured, with the virus contained in parts of the cell’s genome where it can never be replicated back to full power.
One of Yu’s group’s priorities is to find more of these elite controllers and naturally cured people to better understand their biology. But many researchers, including Yu and her colleagues, are already working on strategies to help other people based on what we’ve learned from those with built-in virus resistance. These include therapeutic vaccines that, hopefully, can train the immune system to recognize the reservoirs of HIV.
“The next step will be: How do we use therapeutic vaccines and other approaches to mimic the responses we see in these individuals to a wider patient population?” Yu said. “If we can emulate what we see from elite controllers, not even necessarily these two patients, we can lead people to at least some kind of functional cure before we start talking about a sterilization drug.”
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