HIV positive man becomes second person to be free of virus after stem cell transplant

The man, from London, is the second patient ever to be cured of the virus. The patient, who has not been identified, was diagnosed with HIV in 2003 and started taking drugs to control the infection in 2012. He developed Hodgkin lymphoma that year and agreed to a stem cell transplant to treat the cancer in 2016.

To treat the patient, doctors found a donor who has a gene mutation that makes them naturally resistant to HIV. About 1 per cent of people descended from northern Europeans have inherited the mutation from both parents and are immune to most HIV.

After the stem cell transplant, the patient voluntarily stopped taking HIV drugs to see if the virus would come back. But, he's been free of the virus.

Doctors have reported the successful therapy, saying the man has not taken drugs for the virus for 18 months with no trace of HIV returning. The transplant changed the London patient’s immune system, giving him the donor’s gene mutation and HIV resistance.

According to lead researcher Ravindra Gupta of University College London, the fact the man has been HIV free for 18 months was "an improbable event". 

The therapy has been successful only once before with "Berlin Patient" Timothy Ray Brown, from the US. He was treated in Germany 12 years ago and is still free of HIV.

Timothy Ray Brown, the first patient to be cured of HIV using stem cell transplant

But experts say stem cell transplants are dangerous, have failed in other patients and are said to be an impractical way to try to cure the millions of people already infected.

Stem cell transplants typically are harsh procedures which start with radiation or chemotherapy to damage the body’s existing immune system and make room for a new one.

Complications can also result from the procedure. Timothy had to have a second stem cell transplant when his leukaemia returned. But, compared to Timothy, the unnamed London patient had a less punishing form of chemotherapy to get ready for the transplant, did not have radiation and had only a mild reaction to the transplant.