According to doctors, the unnamed person received a bone marrow transplant from an HIV resistant donor and antiretroviral drugs about 19 months ago.
The London cure report comes more than 10 years after the first case, known as the "Berlin patient" tested negative. In 2007 he underwent a procedure known as hematopoietic stem cell transplantation to treat leukemia, performed by a team of doctors in Berlin, Germany.
According to the report, the patient was diagnosed with HIV in 2003 and was on anti-HIV drugs since 2012.
Stem cell transplants typically are harsh procedures which start with radiation or chemotherapy to damage the body's existing immune system and make room for a new one.
The idea is to use an initial drug to flush out HIV that is hiding from the immune system and then use standard antiretrovirals to kill the newly-exposed virus.
The long remission came after a bone marrow transplant from a CCR5 delta 32 donor in 2016 for Hodgkin's lymphoma, a kind of blood cancer.
Any story about an HIV cure is bound to stir excitement.
According to HIV.gov, there are approximately 1.1 million people in the U.S. living with HIV. With an HIV prevalence of 0.26 per cent in the adult population, India has an estimated 2.1 million people with HIV, shows UNAIDS data.
Researchers learned that Brown and the "London patient" both shared a novel treatment course. "But there is a need for more scientific facts and evidence to be established", V. Sam Prasad, Country Programme Director at AIDS Healthcare Foundation India, told IANS. Most HIV uses both the CD4 and CCR5 receptor to enter a person's immune cells.
Nevertheless, the second case of HIV remission may pave the way for researchers to find a cure for HIV infection.
Dr. Gero Hutter, who treated the first German patient and cured him of HIV applauded this second case and said that it was a "piece in the HIV cure puzzle". "You may have heard of the Chinese babies that were having experimental knockout of that particular gene.What this second case says is this is a bonafide research target and probably the most promising we have for any HIV cure".
There was no evidence of infectious HIV in the gut and lymph nodes of the "Dusseldorf patient" three months after he stopped taking antiretroviral medication, said Annemarie Wensing of University Medical Center Utrecht at a Seattle medical conference.
"Having a bone marrow transplantation is a very complicated process", she said.
However, this avenue for treatment could reportedly never be used as a consistent cure for HIV or Aids, as stem cell transplants are so high risk.
The new patient has chosen to remain anonymous, and the scientists referred to him only as the "London patient". Two factors are likely at play - the new bone marrow is resistant to HIV and also the new bone marrow is actively eliminating any HIV-infected cells through something called graft versus host disease. "Its effectiveness underlines the importance of developing new strategies based on preventing CCR5 expression", said co-author Dr Ian Gabriel (Imperial College Healthcare NHS Trust).