Since the Berlin patient was cured, stem cell therapy and BMT have failed for many HIV-infected people with blood cancer, with the virus rebounding in some cases, and patients succumbing to their leukaemia or lymphoma in others.
He said that despite the patient appearing "functionally cured", it is "too early to say he's cured". There is still no trace of the virus after 18 months off the drugs. "And for people at risk for HIV there are medications they can take that will keep them HIV free".
Millions of people infected with HIV around the world keep the disease in check with so-called antiretroviral therapy (ARV), but the treatment does not rid patients of the virus. Over the three years after the initial transplant, and despite discontinuing antiretroviral therapy, researchers could not detect HIV in Brown's blood.
At the conference in Seattle, Dr. Andrea Cox, an immunologist and professor at Johns Hopkins University in Baltimore, said the British patient's story is an outstanding example of the potential for a cure.
The unnamed man who was given the moniker the "London patient" was diagnosed with the virus in 2003. The transplant modified the London affected person's immune system, giving him the donor's mutation and HIV resistance.More news: Captain Marvel - Movie Review - Captain Marvel Review
"They used a reduced intense conditioning regimen but I think that had no influence on the outcome", he said.
Stem cell transplants are known to be hard on the body, starting with radiation or chemotherapy to damage the existing immune system and make room for a new one.
Now doctors have said that, together, the cases provide proof of concept that a cure may be possible for everyone, although the invasive treatment would have to be adapted radically.
A man in London is now the world's second known patient to be cured of the AIDS virus.
The case comes a decade after Timothy Brown, known in medicine as the "Berlin patient", was cured with a similar stem cell transplant, paving the way for HIV research and revitalizing the search for a cure.More news: Michael Jackson's estate posts live concert footage during 'Leaving Neverland' TV premiere
Johnson explains for the Washington Post, the bone marrow donation not only helped the London patient overcome his Hodgkin's lymphoma, but also equipped him with a genetic mutation known to make cells almost immune to H.I.V. "There is a cost issue for developing countries", he said in a statement.
Rare cases of remission, such as the London and Berlin patients "provide a lot of enthusiasm and motivation" for research teams and show that a cure can be achieved, he said, "but we still have a long way to go".
More than half a dozen US activists, including those who have lived with the illness for decades, emphasized that the development would do little to help those who are now HIV positive, because the procedure can not be administered broadly.
According to reports, the patient is only the second person ever reported to have been cleared of the virus using this method.
Some who have lived with HIV for years said the fact that it can be managed obscures the health complications that can arise from both the virus and its medication.More news: Andrew Bogut nearing a return to the National Basketball Association from native Australia's NBL