Two Australian Patients Reported HIV-Free After Cancer Treatment
Two male Australian patients were reported to be ostensibly free from Human Immuno-deficiency Virus (HIV) following stem cell transplants to treat cancer.
One of the patients was afflicted with non-Hodgkin’s lymphoma and received a bone marrow transplant as treatment in 2011. The donor who gave his replacement stem cells happened to carry a copy of the gene believed to protect against HIV. The second patient received a similar stem cell transplant as treatment for leukemia in 2012.
David Cooper, Director of the Kirby Institute at the University of New South Wales in Sydney, led the discovery and presented his findings at the 20th International AIDS Conference held in Melbourne, Australia. Director Cooper began searching for HIV-freed patients who received stem-cell transplants after hearing similar reports from an AIDS conference in Kuala Lumpur last year. His team examined the archives of Sydney’s St. Vincent’s Hospital, one of the biggest bone-marrow centers in Australia, and found the two men.
The two patients are still taking antiretroviral therapy (ART) as a precautionary measure. However, Director Cooper said that the ART drugs are not solely responsible for keeping the virus levels low. “It is very possible that the Australian men would relapse if they were to stop antiretroviral therapy,” said Timothy Henrich, an infectious-disease specialist at Brigham and Women’s Hospital.
Since cells in the human body are short-lived, it has been a mystery how the virus can survive and hibernate for long periods only to rebound when least expected. Earlier this year a study published in Nature Medicine suggested that the virus might infect stem cells. Research indicates that CD4 T memory stem cells may hide HIV viral reservoirs after antiviral treatment. If the findings are confirmed, the affected cells may present possible targets for future follow-up therapy to eradicate remaining traces of the virus.
“There is something about bone-marrow transplantation in people with HIV that has an anti-HIV reservoir effect, such that the reservoirs go down to very low levels. And if we can understand what that is and how that happens, it will really accelerate the field of cure search,” said Director Cooper.
Another recent study published last month in the Proceedings of the National Academy of Sciences showed how ‘edited’ stem cells can build an HIV-resistant immune system. A team of hematologists used a technique invented by Yuet Wai Kan of the University of California, former President of the American Society of Haematology, and his colleagues. The team hacked into the genome of induced pluripotent stem cells (iPSCs) and produced HIV resistant white blood cells. The researchers said that while the technique offers potential as a cure to HIV, its impact and applications are yet undefined.
Director Cooper said that the Australian patients’ cases are a ‘precious example’ that will help guide research in HIV and its treatment.