The London-based patient becomes the second individual ever to be seemingly cured of HIV over a decade after the first: Timothy Ray Brown, AKA the "Berlin patient," who nearly died after his treatment, according to The New York Times.
The therapy works by effectively replacing the blood cells of an infected person with that of someone who is immune to HIV through a genetic mutation which prevents to virus attaching to cells. He described his patient as "functionally cured" and "in remission", but cautioned: "It's too early to say he's cured". A second, less common form of HIV, could still cause infection despite a transplant like this. "I think so." He says he believes that some HIV still remains in the London patient's body, but that because his immune system is now impervious to the virus, the HIV is marooned - like a castaway on a remote island who can not swim.
"Finding a way to eliminate the virus entirely is an urgent global priority, but is particularly hard because the virus integrates into the white blood cells of its host", Gupta explained.
Both the London patient and the original "Berlin patient" were treated with bone marrow transplants that were meant to treat cancer.
For the London patient, Gupta and his team also found a donor who had these mutations in CCR5.
Chemotherapy can be effective against HIV as it kills cells that are dividing. In these two cases, doctors selected a donor who had an uncommon mutation that made them virtually immune to HIV infection and this mutation was passed on to the recipient.
The man has chosen to remain anonymous, with scientists referring to him as "the London patient".
Regular testing has confirmed that the patient's viral load remained undetectable since then. "We need to understand if we could knock out this [CCR5] receptor in people with HIV, which may be possible with gene therapy", he said.
Timothy Brown, the "Berlin patient", was given two transplants and underwent total body irradiation to treat leukemia, while the British patient received just one transplant and less intensive chemotherapy. The therapy responsible has worked on only one other person who is considered to be "cured" of HIV: Timothy Ray Brown, who still does not show signs of the virus in his body after more than 10 years.
The research was funded by Wellcome, the Medical Research Council, the Foundation for AIDS Research, and National Institute for Health Research (NIHR) Biomedical Research Centres at University College London Hospitals, Oxford, Cambridge and Imperial.
The case was published online by the journal Nature and will be presented at an HIV conference in Seattle. After standard treatments failed, they gave the patient a stem-cell transplant - essentially killing off his old immune system and giving him a new one.