The treatments are also too unsafe, expensive and risky to do for the large number of people who already have the virus that causes AIDS.
The breakthrough comes ten years after the first such case of a patient with HIV going into sustained remission, known as the 'Berlin Patient'.
The researcher, who further explained that the method used is not appropriate for all patients, offered hope for new treatment strategies, including gene therapies. Almost 37 million people have been infected world-wide over the past four decades.
Sixteen months after the man's transplant, doctors found no sign of HIV in his body.
The London-based patient was confirmed HIV-free following a bone marrow transplant from a HIV-resistant donor.
Brown sat in the front row, stood for a round of applause and shook hands with lead researcher Ravindra Gupta of University College London after Gupta presented details on the London patient. He is tested often, and his HIV viral load is undetectable. But with the mutated CCR5, Brown's immune cells became molecular fortresses that HIV couldn't penetrate - which meant the transplant essentially cured him of his infection. Traces of HIV were seen in Brown's blood a few years after he stopped antiretroviral therapy.
But the reason this case is so significant is that it could help experts who are looking for new ways to tackle HIV and achieve a cure. He also naturally had one Δ32 copy, and when similar efforts failed with other patients, there was speculation this, or some other rare feature of Brown's case, was required for success.
The London Patient has chosen to remain anonymous.
"I never thought that there would be a cure during my lifetime", he said.
Both Brown and the London patient underwent bone marrow transplants because they needed to treat their cancer, not to treat their HIV; and both experienced side effects of rejection at varying levels, since they received cells from an unrelated donor. This news arrived via a research paper published by the man's doctors.
He said: "But what we are able to say with certainty is that, through early diagnosis and access to treatment, you can live a long, healthy life with HIV and be confident you won't pass the virus to your sexual partners".
This could lead to a simpler approach that could be used more widely, added Jerome, who was not involved in either case.
"There are actually many strategies right now that are currently being pursued", Henrich said.
But in the case of the London patient, the treatment worked.
Scientists are also examining immune modifying therapies. "So while it's truly aspirational, I wouldn't say it's out of the realm of possibility".