Patient HIV free after stem cell therapy
A second HIV sufferer appears to be free of the disease after receiving a bone marrow transplant.
Scientists are warning that it is too early to say whether the patient has been cured permanently, but early signs seem positive.
The patient, who has not been identified, received a stem-cell transplant that replaced their white blood cells with ones resistant to HIV.They stopped taking antiretroviral drugs 18 months ago, and have since shown no signs of the virus. This is the second person to have undergone the treatment successfully after it was first used 12 years ago on American citizen Timothy Ray Brown, who is still free of the virus.
In a paper published in the journal Nature, the researchers – led by Ravindra Gupta, Wellcome Trust senior fellow in clinical science at University College London – reported that the virus disappeared from the patient’s blood after the transplant. In the lab, they were unable to reinfect the patient’s cells with HIV.
After 16 months, the patient stopped taking antiretroviral drugs, the standard treatment for HIV, which means they have now been free of the disease for almost three years.
Natural resistance
In both cases, the doctors treating them chose a donor who had two copies of a genetic mutation that provides resistance to HIV. The mutation occurs in a gene called CCR5, and hampers the virus’ ability to enter and attack white blood cells.About 1 in 100 people of northern European descent have two copies of this mutation, which is particularly common among Swedish people and, interestingly, predates the existence of HIV in humans.Another 10 to 15% are thought to have inherited one copy, which provides some immunity and delays the progress of AIDS. The mutation has not been found in Africans, East Asians, or Native Americans.
A risky treatment
Both Brown and the latest patient already needed a bone marrow transplant to cure blood cancer, by replacing their blood cells with cells transplanted from a healthy donor. As such, scientists have warned that the treatment would only be suitable for a very small number of people.
It’s too risky to help most people who are infected with HIV, as a bone marrow transplant is in itself a serious and dangerous procedure that can have fatal complications.Before a transplant, patients are given drugs and radiation to destroy their own cells, which leaves them vulnerable to infection. There is also the possibility that their bodies will eventually reject the transplant.
As Graham Cooke, a clinical researcher at Imperial College London, told Nature: “If you’re well, the risk of having a bone marrow transplant is far greater than the risk of staying on tablets every day.” Most people with HIV respond well to daily antiretroviral treatment, although the drugs do have side effects.
Collaborative efforts
Haematologist Gero Hütter led Brown’s treatment in Germany and performed the pioneering transplant on February 7, 2007.Yet he is an oncologist, not an HIV specialist – when he realised Brown would need a transplant, he happened to remember a paper he had read in the early 1990s about HIV resistance and the CCR5 mutation. The paper had made a big impression on him at the time – it was the height of the epidemic, before antiretrovirals had been developed, and AIDS was killing people at terrifyingly young ages.
A cure was still considered so unlikely that it took almost a year after Hutter first reported the results of Brown’s transplant for a medical journal to publish his paper. If you’re carrying out groundbreaking medical research, you could be eligible for government funding through the research and development tax credits scheme. At R&D Tax Solutions, we specialise in helping companies make successful claims. Have a look at our research and development tax relief examples and r&d tax credits calculator to see how much you could be eligible for – and contact us to see how we can help.