Doctors said a London man with HIV has become the second known adult in the world to be apparently cleared of the infection since the global epidemic began decades ago, giving hope for a potential cure for AIDS.
Virologist Ravindra Gupta at University College London, who is scheduled to describe the London patient's case tomorrow at the Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, Washington, and online in Nature, resists using the term "cured" for the man, who remains anonymous.
The breakthrough comes ten years after the first such case of a patient with HIV going into sustained remission, known as the 'Berlin Patient'. To treat the cancer, the London patient agreed to a treatment called a stem cell transplant.
A new report surfaced saying a man who is HIV positive is now remission after receiving a bone-marrow transplant.
"The first is that CCR5-negative cells are resistant to HIV", she said. Millions of people are HIV positive, ... And we've already identified individuals with cells that can't be infected by HIV (they have a mutation that damages or eliminates a protein that HIV uses to attach to cells), who can act as a source of HIV-resistant cells.
Timothy Henrich, a clinician at the University of California, San Francisco (UCSF), has seen HIV bounce back in two patients who had a conditioning regimen that impressively knocked down HIV reservoirs but whose transplants came from donors with working CCR5s. Four years later, doctors gave him a bone marrow transplant, and luckily for him, his donor for the marrow had natural immunity to HIV. Unlike for Brown, radiotherapy wasn't required and the London patient experienced far less severe consequences than Brown, but Gupta believes the chemotherapy used against the lymphoma was an essential part of its success, temporarily destroying fast-dividing cells so replacement could occur.
But a second instance of remission and likely cure following such a transplant will help scientists narrow the range of treatment strategies, he and others said. He was diagnosed with the cancer in 2012.
Any story about an HIV cure is bound to stir excitement. Many populations of blood and immune cells are replaced regularly. Timothy Brown, an American man, was known as "the Berlin patient" when he also received a bone marrow transplant for leukemia treatment in Germany 12 years ago.
The CCR5 gene, and the eponymous cell it codes for, nearly certainly play a crucial role in the collateral HIV cure. But HIV drugs have become so effective that many people carrying this infection have a normal lifespan if they take these medications for a lifetime. The London patient is one of 40 in the study.
The researchers say the latest findings show that Brown's case was not a one off, and that there are ways to target the CCR5 receptor to treat HIV.
The London patient has no detectable HIV virus, Gupta and colleagues said. "It shows the Berlin patient was not just a one-off, that this is a rational approach in limited circumstances", Daniel Kuritzkes, chief of infectious diseases at Brigham and Women's Hospital (who was not involved in the study), told the paper.