HIV Cure Study Provides Insight into 2008 Case

CNN/ Newswire | 7/18/2016, 11:43 a.m.
In 2008, one man, Timothy Ray Brown, was cured of HIV. Also known as the "Berlin patient," Brown was considered ...

By Meera Senthilingam

for CNN

(CNN) -- In 2008, one man, Timothy Ray Brown, was cured of HIV.

Also known as the "Berlin patient," Brown was considered cured of his infection after receiving two bone-marrow transplants to treat a separate disease he had been diagnosed with a few years earlier: acute myeloid leukemia.

The bone marrow he received came from a donor whose genes carried a rare mutation that made them resistant to HIV, known as CCR5-delta 32, which was transferred on to Brown.

Traces of the virus were seen in his blood a few years later, but remained undetectable despite him not being on antiretroviral treatment, meaning he was still clinically cured of his infection, according to his clinicians.

Despite various attempts on patients after him by scientists using this same approach, including a similar transplant in two Boston patients, Brown remains the only person known about who has been cured of HIV.

But a new study presented Sunday at the 2016 Towards an HIV Cure Symposium -- ahead of the 21st International AIDS conference in Durban, South Africa, this week -- revealed data on a new set of HIV positive patients whose reservoirs of HIV have fallen to very low levels after receiving a range of stem cell transplants similar to Brown's.

The study is part of the EPISTEM project, a European project to investigate the potential for an HIV cure using stem cell transplantation, and provides further insight into the science underlying Brown's success.

Everyone included in the project is in need of stem cell transplantation to cure severe blood disorders, in addition to being infected with HIV.

Can stem cells bear a cure?

The 15 patients monitored in the study to date are still on antiretroviral treatment, unlike Brown, but have received stem cell transplants. Three of them had their operations three years ago and have been studied in detail since.

"In two of the three patients we were unable to detect infectious virus in the blood of the patients," said Annemarie Wensing, a virologist at the University Medical Center Utrecht who led the study. Tissue samples were also studied and one patient also had just traces of the virus hiding there.

"All HIV-infected patients that received a stem cell transplantation had a significant reduction of the viral reservoir in their body. This has not been demonstrated with other cure strategies," Wensing said.

The minute levels of the virus that have been seen to date were not considered competent enough to replicate, according to the team.

"[This] will help us shape future HIV eradication strategies that could be applied at a larger scale than stem cell transplantation," said Wensing.

But there's a long road ahead.

"What's interesting is that these patients have survived more than a year," said Sharon Lewin, director of the Peter Doherty Institute for Infection and Immunity and co-chairwoman of the symposium. "There was concern that maybe when you take a CCR5-delta32 bone marrow it doesn't engraft as well, but these patients have survived to 12 months."