Like Timothy Ray Brown, the first-and, until now, only-individual to undergo successful H.I.V. therapy, the so-called "London patient" actually received his stem cell transplant to treat an unrelated form of cancer.
For the second time since the global epidemic begun, scientists claim to have "cured" a HIV patient. The donor has two mutated copies of the CCR5 Δ32 allele, so the person is resistant to the HIV-1 virus strain that uses the CCR5 receptor since the virus can not enter the host cells. This gene codes for a receptor which sits on the surface of white blood cells involved in the body's immune response.
Dr. Sarah Fidler, a professor in HIV medicine at Imperial College London, says a bone marrow transplant would be too unsafe for patients who are healthy and taking a daily pill to treat HIV.
However, following a stem cell transplant in 2016 after he had developed Hodgkin's lymphoma, the HIV virus was no longer in the system.
"The transplant resulted in the complete destruction of the old immune system and the construction of a new immune system in which the (HIV) virus can't replicate (because of the genetic mutation)". But with only two cases of people who have been cured of HIV - and the British patient has been "cured" just 18 months - he said it's too soon to tell where this might lead. Most HIV uses both the CD4 and CCR5 receptor to enter a person's immune cells. The aim is to get everybody on treatment for the rest of their lives and that's a huge undertaking both for drug delivery but also making sure people can stay on medication for decades. The incoming transplanted donor-immune cells seek out and destroy all the host's immune cells - including those in which HIV can hide out, he said.
About 37 million people worldwide are infected with HIV. More recently, researchers reported that a bone marrow transplant recipient in Minnesota had viral remission lasting almost 10 months after an analytic treatment interruption, but he too ultimately experienced viral rebound.
"I did not want to be the only person in the world cured of HIV", Brown wrote in a medical journal in 2015, explaining why he made a decision to reveal his identity.
Gupta said the treatment is not appropriate for all patients, but it offers hope for a possible cure for everyone living with the disease.
This new case in London also used a stem cell transplant.
The research team is presenting the findings today (March 5) at the annual Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle.
The patient, known only as "London patient" reportedly prefers to remain anonymous. However, this new case adds to the evidence that using gene therapy to delete CCR5 receptors from T cells may be a feasible approach.
Teams in labs around the world, as well as drug companies including Gilead Sciences, Johnson & Johnson and GSK's ViiV Healthcare, have very early-stage cure studies in the works, said Rowena Johnston, director of research at U.S. AIDS research foundation amfAR.