Scientists reported last week that a woman of mixed race had become the third person believed to be cured of HIV through the use of a stem cell transplant from a donor naturally resistant to the virus. Success with the new umbilical cord blood technique could allow physicians to assist more patients of various genders and races.

AIDS-causing virus HIV has previously been treated in two patients who appeared to have recovered using a different procedure. When Timothy Brown and Adam Castillejo were diagnosed with HIV, they were given bone marrow transplants from donors with a genetic mutation that prevents HIV infection. Adult hematopoietic stem cells can be found in bone marrow and umbilical cord blood, which are supplied by the parents of newborns. All of the immune system’s blood cells are derived from these stem cells.

A donor with natural immunity to HIV was chosen for the female patient’s umbilical cord blood treatment for leukaemia in the belief that it would help her battle both illnesses. It’s been 14 months since the woman, who prefers to remain anonymous, has been rid of the virus, according to specialists.

The two male patients were the first to be cured of HIV with the use of umbilical cord blood, a less intrusive and more generally available therapy option than the more invasive bone marrow transplant. Because cord blood donors aren’t as closely matched to the recipient as bone marrow donors, it can be an alternative for patients with unusual tissue types.

AIDS expert Steven Deeks, who was not involved in the study, said: “The fact that she’s mixed race, and that she’s a woman, that is incredibly important scientifically and really important in terms of the community impact.”

In contrast to Brown and Castillejo, the woman was discharged from the hospital 17 days following her bone marrow transplant without showing any signs of graft-versus-host disease. It was a stem cell transplant that saved the lives of all three individuals who appeared to have beaten HIV.

Despite the apparent success of the medication, most of the 38 million people living with HIV around the world will not be able to benefit from it at the moment. HIV patients who receive cord blood stem cell transplants for cancer treatment are part of a bigger study that will follow a total of 25 people with HIV who receive transplants for aggressive malignancies like leukaemia.

Koen van Besien, director of Weill Cornell Medicine’s stem cell transplant programme and one of the clinicians engaged in therapy, estimates that there are roughly 50 individuals in the US each year that could benefit from this technique. For these individuals, the use of cord blood grafts that are only partially matched dramatically increases the chance of finding a compatible donor.