Man cured of HIV by marrow transplant

The American man, who lives in Berlin, had HIV but was given the blood stem cell transplant in 2007 to treat leukaemia. His donor not only was a good blood match but also had a gene mutation that confers natural resistance to HIV.

Now, three years later, the recipient, who is in his 40s, shows no signs of leukaemia or HIV infection, according to a report in the journal Blood.

Around three-and-a-half years after ending anti-retroviral therapy, the patient has no sign of infection.

German scientists led by Dr Kristina Allers, from Charite-University Medicine Berlin, wrote in the journal Blood online: "From these results, it is reasonable to conclude that cure of HIV infection has been achieved in this patient."

The donor stem cells replaced the patient's HIV-infected population of CD4 white blood cells. The stem cells had a genetic variant known to prevent invasions by the HIV virus.

After the transplant, it was found that HIV replication in the patient had stopped. Doctors, however, had expected the virus to return as the patient's cancer-damaged immune system was being rebuilt but this did not happen. Instead scientists found successful reconstitution of "healthy" CD4 cells throughout the patient's body.

CD4 cells activate and direct other elements of the immune system. The researchers wrote: "By monitoring the most common prognostic markers, HIV cannot be assessed in this patient."

Dr Andrew Freedman, from Cardiff University School of Medicine, said: "A cure for HIV, as opposed to lifelong suppressive therapy, has long been sought after. This single case report shows that this is achievable but the stem cell transplant procedure involved is much too complex, risky and expensive for routine use."