Some people with HIV have a seemingly miraculous ability to control the disease without lifelong antiviral drugs like risky bone marrow transplants, and now a new study shows how this “elite” group manages the infection.
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illustration of HIV and human DNA
In less than 0.5% of people with HIV, the virus stops replicating without the need for medication, although some latent virus remains in the body, according to the study, published Aug. 26 in the journal Nature. HIV hides itself in human genes, but new research suggests that these genes sometimes infect the pathogen in regions of the genome where it cannot be copied, reports The New York Times, and prevents the virus from replicating the infection and under control.
For one patient, researchers were unable to detect traces of the virus in blood cells, or in cells from their intestines or rectum, the Times reported. The 66-year-old patient, named Loreen Willenberg, has successfully suppressed the virus for decades and has been involved in HIV studies for more than 25 years.
Although scientists have known about her case for years, data from the new study suggest that she may often be considered “cured” of the infection. To date, only two people in the world are considered cured of HIV, and both have undergone bone marrow transplants to make their immune system resistant to the virus, Live Science reported earlier. Willenberg would join the shortlist of fully recovered HIV patients if they could be confirmed free of the virus.
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“She could be added to the list of what I think is a drug, via a very different path” compared to bone marrow transplantation, Dr. Sharon Lewin, director of the Peter Doherty Institute for Infection and Immunity, who was not involved in the study, told the Times.
On the other hand, virologist Dr. “It’s certainly encouraging, but speculative,” O’Doherty told the Times.
The authors of the study speculated that some people taking antiviral drugs for HIV could potentially achieve recovery as Willenberg might have, if the virus contained in them in the same way in genetic prisons could not replicate. And in fact, about 10% of people who control HIV with drugs can eventually stop taking antiviral drugs and continue to suppress the virus without support, according to The New York Times; the new study points out how that may be possible.
“It does suggest that treatment can cure people, which is against all dogma,” said student author Dr. Steve Deeks, an AIDS expert at the University of California, San Francisco, The Times.
In addition to Willenberg, the study included 63 other people who suppressed the virus without antiviral drugs, the Times reported. Among the 64 patients, 11 stood out as “exceptional controllers;” these individuals had only detectable levels of the virus in densely packed regions of the genome where cells did not have easy access. Normally, HIV would cut down the cellular machinery used to make egg whites instead of making copies of themselves, but if HIV genes are sequenced by certain genes, the pathogen has no way of replicating.
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By analyzing the immune cells of participants in the study, the authors came up with a theory about how the virus hangs in the first place. They suspect that, in some people, immune cells known as T cells target and kill infected cells that carry HIV in easily accessible parts of the genome – in regions where it can be copied. HIV remained untouched in cells where it was trapped in “blocked and locked” regions of the genome, said senior author Dr. Xu Yu of the Ragon Institute de Times.
“That’s actually the only explanation” the researchers have as to why the virus would persist in some cells without replicating, said student author Dr. Bruce Walker, a researcher at the Ragon Institute, The New York Times.
Since submitting the results of their study, the authors have found several other people like Willenberg who can be effectively cured of HIV, Yu told The New York Times. “We believe there are absolutely a lot of them,” he said. The team also aims to study people with HIV who have been taking antivirals for decades, to see if their immune systems have locked up the virus in genetic prisons in the same way.
Still, it is unclear if the findings could translate to most people with HIV. “The real challenge, of course, is how you can intervene to make this relevant to the 37 million people living with HIV,” Lewin told the Times. In other words, could these findings pave the way for a functional cure for others with the disease? We need more data to know for sure.
Originally published on Live Science.
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