A woman of mixed race appears to be the third person ever to be cured of HIV, using a new transplant method involving umbilical cord blood that opens up the possibility of curing more people of diverse racial backgrounds than was previously possible, scientists announced Tuesday.

Cord blood is more widely available than the adult stem cells used in the bone marrow transplants that cured the previous two patients, and it does not need to be matched as closely to the recipient. Most donors in registries are of Caucasian origin, so allowing for only a partial match has the potential to cure dozens of Americans who have both HIV and cancer each year, scientists said.

The woman, who also had leukemia, received cord blood to treat her cancer. It came from a partially matched donor, instead of the typical practice of finding a bone marrow donor of similar race and ethnicity to the patient’s. She also received blood from a close relative to give her body temporary immune defenses while the transplant took.

Researchers presented some of the details of the new case Tuesday at the Conference on Retroviruses and Opportunistic Infections in Denver.

The sex and racial background of the new case mark a significant step forward in developing a cure for HIV, the researchers said.

“The fact that she’s mixed race, and that she’s a woman, that is really important scientifically and really important in terms of the community impact,” said Dr. Steven Deeks, an AIDS expert at the University of California, San Francisco who was not involved in the work.

Infection with HIV is thought to progress differently in women than in men, but while women account for more than half of HIV cases in the world, they make up only 11% of participants in cure trials.

But Deeks said he did not see the new approach becoming commonplace. “These are stories of providing inspiration to the field and perhaps the road map,” he said.

There have only been two known cases of an HIV cure so far. Referred to as “The Berlin Patient,” Timothy Ray Brown stayed virus-free for 12 years, until he died in 2020 of cancer. In 2019, another patient, later identified as Adam Castillejo, was reported to be cured of HIV, confirming that Brown’s case was not a fluke.

This article originally appeared in The New York Times.

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