A second set of "Boston patients", who received stem cell transplants with functioning CCR5 genes, also experienced marked reductions in the reservoir of HIV in their cells - and were able to go without treatment for months, showing that the transplant itself played a role in knocking back the virus.
The patient has shown no trace of previous HIV infection since he underwent the transplant operation three years ago.
Sixteen months after the procedure (which notably didn't include radiotherapy, unlike the Berlin patient), the London patient discontinued ARV drugs (aka ART therapy), and has now been in HIV remission for over 18 months. Bone marrow from a similarly CCR5 negative donor was given to the "London Patient". His transplant beat cancer without any threatening side-effects, and the transplanted immune cells that were made resistant to HIV appeared to have replaced all the HIV-vulnerable cells in his blood.
The London Patient has not been named yet, but Brown hopes both men will meet one day, but just not yet on account of publicity concerns.
The approach is not appropriate as a standard HIV treatment due to the toxicity of chemotherapy, he warned, but said he is "hopeful" it will help them develop strategies that might eliminate HIV altogether. The London patient ultimately had no option but to try the experimental treatment when he was diagnosed with Hodgkin's lymphoma in 2012.
The second person, dubbed "The London Patient", was treated by specialists at the University College London and Imperial College in 2016 and has shown no sign of the virus since. People with two copies of the Δ32 mutation of CCR5 gene are resistant to HIV-1 infection.
After news of the first "Berlin patient" broke at the same Seattle Conference in 2007, scientists have been trying hard to replicate the results in other HIV-infected patients. That means the London patient may have HIV remaining that can use CXCR4 to infect cells, giving the virus a way to start flourishing again.
This comes 12 years after the first success case of Timothy Ray Brown - a US-based man treated in Germany's Berlin, a feat researchers failed to duplicate.
The aggressive therapy was primarily used to treat the patient's cancer, not his HIV.
But rearming the body with immune cells similarly modified to resist HIV might well succeed as a practical treatment, experts said.
Yet it is too early to confirm whether or not the patient is indeed "cured" of the virus which causes AIDS, news.com.au reports.
"I think this does change the game a little bit", Gupta opined to NYT of the new patient, who had less invasive treatment than Brown.
The London Patient was given stem cells from a donor with genetic resistance to the disease.
So far, its scientists are tracking 38 HIV-infected people who have received bone-marrow transplants, including six from donors without the mutation.