Three years after receiving a stem cell transplant, a man from London is the second patient in history to be cured of HIV, doctors report.
The study, published in the Lancet HIV, reports that the so-called 'London patient' has no detectable active HIV infection – in blood, semen, or tissues – 30 months after stopping anti-retroviral therapy. This follow-up comes a year after the first publication in Nature announcing he was clear of the virus (see BioNews 990).
'We've tested a sizeable set of sites that HIV likes to hide in and they are all pretty much negative for an active virus,' the study's lead author Dr Ravindra Gupta, from the University of Cambridge, told AFP. 'We propose that these results represent the second ever case of a patient to be cured of HIV.'
Adam Castillejo – who recently decided to go public with his identity in the New York Times – had been diagnosed with HIV in 2003 and then additionally with advanced Hodgkin's Lymphoma in 2012. After failed rounds of chemotherapy and attempts to transplant his own stem cells, he received a donor stem cell transplant in 2016 to treat his blood cancer. Similar to the 'Berlin patient' (the first person known to be cured of HIV) in 2011, the transplant came from a donor carrying a rare genetic mutation present in less than one percent of Europeans, which prevents HIV from entering the affected cells via the CCR5 receptor.
'This is a unique position to be in, a unique and very humbling position,' Castillejo told the New York Times. 'I want to be an ambassador of hope.'
Now, 30 months after cutting off retroviral therapy, the doctors reported no active infection in Castillejo's blood, cerebrospinal fluid, semen, intestinal tissue, or lymphoid tissue. Whatever traces of virus material could be found in the system are likely so-called fossil traces, which cannot replicate and harbour no risk of reoccurrence of the infection.
Dr Gupta said that this is to be expected. 'It's quite hard to imagine that all trace of a virus that infects billions of cells was eliminated from the body,' he explained.
Scientists agree that stem cell transplants will not be a feasible treatment for the millions of people around the world infected with the virus. With a ten percent mortality rate, bone marrow transplants are mainly used to treat cancer patients when no other options are available, and current antiviral drugs can enable HIV patients to live long and healthy lives. However, observing these 'cured' patients could provide helpful insights for the design of future genome editing tools to treat and cure HIV.
Professor Sharon Lewin from the University of Melbourne, Australia, said the case was exciting but warned: 'We need to also place it in context - curing people of HIV via a bone marrow transplant is just not a viable option on any kind of scale. We need to constantly reiterate the importance of, prevention, early testing and treatment adherence as the pillars of the current global response to HIV/AIDS.'