Back in 2009, doctors published a report in the New England Journal of Medicine detailing the case of the "Berlin patient" - an HIV-positive man who'd received a stem cell transplant to treat his leukemia.
"It is a landmark". Still, the London case shows that "HIV cures are possible", he said.
The team is presenting the findings at the annual Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, US this week.
Globally, 36.9 million people were living with HIV at the end of 2017, with 59 percent receiving antiretroviral treatment, according the World Health Organization. A variety of "reservoirs" of HIV-infected cells has been identified; all of the significant ones appear to be in immune cells of one type or another.
The CCR5 gene, and the eponymous cell it codes for, nearly certainly play a crucial role in the collateral HIV cure.
Ravindra Gupta and his colleagues write, "it is premature to conclude that this patient has been cured", but they are hopeful that will prove to be the case.
"There are a number of learning points here", he said. He underwent the bone marrow transplant and later was declared free of HIV. Unlike Brown, though, the London patient did not have to go through a horrific, near-death experience to reap the benefits of the therapy. As a result, when the London patient received the stem cells, his immune system changed and he developed a natural resistance to HIV, too.
In 2016, he received a transplant of haematopoietic stem cells from a donor carrying a genetic mutation in the HIV receptor CCR5, which hinders the HIV virus from entering human cells.
"For hepatitis C, we can completely cure people of the virus so they're no longer infected".
"We know that CCR5 can be knocked out without any serious consequences because people are walking around without that gene".
This receptor was recently in the news after Chinese scientist He Jiankui claimed he'd edited the genes of embryos to include a protective version of CCR5. # # # The mission of the International AIDS Society (IAS) is to lead collective action on every front of the global HIV response through its membership base, scientific authority and convening power.
"We can try to tease out which part of the transplant might have made a difference here, and allowed this man to stop his anti-viral drugs", she added.
Scientific research into the complex virus has led to the development of drug combinations which have been able to not only keep it at bay in most patients, but also prolong the lives of many others.
But scientists were keen to stress that the technique is likely only viable among a tiny percentage of sufferers. "It shows the Berlin patient was not just a one-off, that this is a rational approach in limited circumstances", said Daniel Kuritzkes, chief of infectious diseases at Brigham and Women's Hospital, who was not involved in the study.
"However, this work has the potential to stimulate research into more generally applicable therapies".
Dr Gupta, a virologist at University of London, described the cure as "remission", a term normally used with cancer patients to mean that one is not cancer free, as the cancer cells are still in the body but inactive.
"Expanding remission to populations that are affected disproportionately is quite important", he told AFP.