A 30-year-old woman from the city of Esperanza, Argentina — the so-called Esperanza Patient — appears to be the second person whose immune system cleared the HIV-1 virus without antiretroviral therapy.
Scanning electron micrograph of an HIV-infected H9 T cell. Image credit: NIAID.
“During infection, HIV places copies of its genome into the DNA of cells, creating what is known as a viral reservoir,” said senior co-author Dr. Xu Yu, a researcher at Ragon Institute of MGH, MIT and Harvard Brigham and Women’s Hospital, and her colleagues.
“In this state, the virus effectively hides from anti-HIV drugs and the body’s immune response.”
“In most people, new viral particles are constantly made from this reservoir.”
“Antiretroviral therapy can prevent the new viruses from being made but cannot eliminate the reservoir, necessitating daily treatment to suppress the virus.”
“Some people, known as elite controllers, have immune systems that are able to suppress HIV without the need for medication.”
“Though they still have viral reservoirs that can produce more HIV virus, a type of immune cell called a killer T cell keeps the virus suppressed without the need for medication.”
In 2020, Dr. Yu and co-authors identified the first elite controller who had no intact HIV-1 viral sequence in her genome, indicating that her immune system may have eliminated the HIV-1 reservoir — what the scientists call a sterilizing cure.
The researchers sequenced billions of cells from that patient — known as the San Francisco Patient — searching for any HIV-1 sequence that could be used to create new virus, and found none.
The newly-identified patient, like the San Francisco Patient, has no intact HIV-1 genomes in a total of 1.188 billion peripheral blood mononuclear cells and 503 million mononuclear cells from placental tissues.
“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,” Dr. Yu said.
“The results may suggest a specific killer T cell response common to both patients driving this response, with the possibility that other people with HIV have also achieved a sterilizing cure.”
“If the immune mechanisms underlying this response can be understood by researchers, they may be able to develop treatments that teach others’ immune systems to mimic these responses in cases of HIV infection.”
“We are now looking toward the possibility of inducing this kind of immunity in persons on antiretroviral therapy through vaccination, with the goal of educating their immune systems to be able to control the virus without antiretroviral therapy,” she said.
The team’s paper was published in the Annals of Internal Medicine.
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Gabriela Turk et al. A Possible Sterilizing Cure of HIV-1 Infection Without Stem Cell Transplantation. Annals of Internal Medicine, published online November 16, 2021; doi: 10.7326/L21-0297
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