According to the research, which was published Monday in the journal Nature, nearly three years after receiving a stem-cell transplant from a donor who was genetically resistant to HIV, extensive testing shows that the man, whose identity was not revealed, has no detectable sign of the virus. After HIV-resistant blood cells derived from the transplant supplanted the recipients' vulnerable cells, the two patients stopped taking the antiretroviral (ARV) drugs that had been damping down their infections. The London patient has not been off his antiretroviral drugs for 18 months, but has shown no signs of HIV despite regular testing. Like the London patient, he had a bone marrow stem cell transplant to treat cancer. This indicates that other patients, in the same circumstances, should, where possible, receive transplants from a donor with this same gene mutation.
For now, the patient has chosen to remain anonymous and he's being called the "London Patient".
Blood cells of an infected person are replaced by someone who is immune to HIV through a genetic mutation which stops the virus attaching to cells.
Both cases involved a risky procedure called a stem-cell transplant (otherwise known as a bone marrow transplant).
Dr. Gero Hütter, who treated the Berlin patient and is now medical director at Cellex Collection Center in Dresden, Germany, said in an email that the treatment used for the London patient is "comparable" to the one he pioneered.
The case was published online Monday by the journal Nature and will be presented at an HIV conference in Seattle.
The CCR5 gene was thrust into the global spotlight recently by the revelation that a Chinese scientist had attempted to edit human embryos to create the same deletion, with the hopes of creating babies that were immune to HIV. Indeed, 16 months later, his virus remains at below detectable levels, and his immune cells all contain the HIV-fighting CCR5 mutation. Those patients could benefit if they can find a donor with the rare mutation in CCR5 that protects them from HIV re-infection. The longer treatment is delayed, the greater the chance that HIV can also mutate to use CXCR4 and CCR5 to infect cells. Both the Berlin and London patients had this complication, which may have played a role in the loss of HIV-infected cells, Gupta said.
He is tested often, and his HIV viral load is undetectable.
The therapy had an early success with Timothy Ray Brown, a USA man treated in Germany who is 12 years post-transplant and still free of HIV. The vast majority of HIV strains use normal copies of this gene to gain entry to a patient's immune-system cells, WSJ said.
So far, 38 people living with HIV have received bone marrow transplants from one of these donors, and their progress is being tracked. Currently, there are powerful and effective drugs available to control HIV infection with few or no side-effects.
Gupta described his patient as "functionally cured" and "in remission", but cautioned, "It's too early to say he's cured". "Some of them are directly related to the Berlin patient and work with transplantation: for example, gene modification therapy".
Sharon Lewin, an expert at Australia's Doherty Institute and co-chair of the International AIDS Society's cure research advisory board, told Reuters news agency the London case points to new avenues for study.