UK researchers have confirmed that a stem cell transplant has cured a second HIV individual.
Timothy Ray Brown became the first person ever confirmed by doctors as being cured of HIV in 2007. At the time they openly referred to him as the patient in Berlin.
His path toward a cure was not clear. Mr. Brown was given antiretroviral treatment after being diagnosed with HIV in the 1990s— the normal course of action for an HIV infection.
Later, however, he was also diagnosed with acute myeloid leukemia, for which he ultimately received a stem cell transplant.
His doctor had the idea to try an experiment, as he was looking for a suitable donor match. He sought a donor with a specific genetic mutation that would make them virtually immune to HIV.
It turned out that receiving stem cells from this donor not only treated leukemia from Mr Brown but also healed the HIV infection.
Now, as a study featuring in The Lancet shows, another person was officially cured of HIV, also thanks to a transplant of stem cells.
‘Success of stem cell transplantation’
In this second case, the person received a transplant of stem cells with cells that did not express the CCR5 gene, which produces a protein that helps the virus enter the cells.
The cells without the CCR5 gene were part of a bone marrow transplant which the individual underwent as a Hodgkin lymphoma treatment.
After the transplant, and 30 months after the person stopped antiretroviral therapy, doctors confirmed that the HIV viral load in blood samples remained undetectable.
This finding means that whatever traces of the genetic material of the virus may still be in the system, they are so-called fossil traces which means that they can not lead to further virus replication.
The specialists confirmed that HIV in samples of cerebrospinal fluid, semen, intestinal tissue and lymphoid tissue also remained undetectable.
“We propose that these results represent a patient’s second ever case to be cured of HIV,” says lead author of the study, Prof. Ravindra Kumar Gupta, from Cambridge University in the UK.
“Our findings show that the success of stem cell transplantation as a cure for HIV, first reported 9 years ago in the Berlin patient, can be replicated.”
– Prof. Ravindra Kumar Gupta
Nevertheless, Prof. Gupta stresses that”[ i]t is important to note that this curative therapy is high-risk and used only as a last resort for HIV patients who also have life-threatening hematological[ blood] malignancies.”
“Therefore, this is not a medication that would be commonly provided to HIV patients who are on effective antiretroviral treatment,” the researcher goes on to warn.
Reflecting on these results, other researchers involved in the study expressed the hope that scientists could use state-of- the-art gene editing techniques as part of therapies aimed at treating and curing HIV in the future.
Dr Dimitra Peppa, who is from Oxford University, UK. The research was co-authored, adding that”[ g]ene editing using CCR5 has recently received a great deal of attention.”
But, she points out, there is still a long way to go before these therapies can become feasible.
“There are still many legal and technological hurdles to address before any solution using CCR5 gene editing can be considered as a viable HIV cure strategy,” she says.
