Mr Brown said he would like to meet the London patient and would encourage him to go public because "it's been very useful for science and for giving hope to HIV-positive people, to people living with HIV".
Mr Brown underwent similar treatment to the "London patient" in Germany in 2007, which also cleared his HIV.
The doctors selected a donor who had two copies of a particular mutation in the CCR5 gene that prevents HIV from infecting T-cells, a part of the immune system where the virus takes hold and does its damage.
As with cancer, chemotherapy can be effective against HIV as it kills cells that are dividing.
Fauci sees the report of the London patient as being less about the possible benefits of bone marrow transplants in treating or even curing HIV, and more about the need to focus HIV research on CCR5.
"The so-called London Patient has now been off ART for 19 months with no viral rebound which is impressive, but I would still be closely monitoring his viral load", said Lewin, who is also co-chair of the International AIDS Society's Towards an HIV Cure initiative.
It was only in 2016 that he was able to access the stem cell donation because he was seeking treatment for the cancer, not the HIB.
The man - who wishes to remain anonymous - was given stem cells from a donor with genetic resistance to the disease and he has now been in long term remission for 18 months without medication. "After 2 years, we'll be talking more about 'cure, '" Gupta says. Some seemed to control the infection without ARVs for a period but later had the virus rebound or died from their leukemia or lymphoma.
"Common to both approaches is the presence of a modified gene in our immune system (CCR5) that is necessary for HIV infection".
"Although it is not a viable large-scale strategy for a cure, it does represent a critical moment in the search for an HIV cure".
That didn't happen with the London patient.
Andrew Freedman, from the U.K.'s Cardiff University, said the case was interesting and potentially significant.
A second person has experienced sustained remission from HIV-1, according to a case study to be published Tuesday in the journal Nature. "Some of them are directly related to the Berlin patient and work with transplantation: for example, gene modification therapy". "Durable engraftment" of the CCR5 mutants is key to a cure, he concludes.
Combined with past cases (one successful and one failed), we can now say something about what needs to be done to get rid of the virus.
He's being the only one thought to have been cured of HIV. "That could be a fantastic way forward", Johnston says.
Possibly. The London patient's immune system is now created to block HIV's most common path into cells, using the CCR5 receptor. This makes it a tricky and unfeasible option as a treatment for other HIV-positive patients in the near future. So far, there are only two known instances of a reported cure.