Two New Stem Cell Transplant Cases Expand HIV Cure Count to 13

Two patients have joined a small but growing roster of people whose bodies appear to have cleared HIV following stem cell transplants performed to treat blood cancers. Researchers presented the cases this summer at the International AIDS Conference, and if the patients remain free of detectable virus, they will be the 12th and 13th documented instances of HIV remission or cure achieved through this procedure.

The first patient, identified as the Kansas City Patient, tested positive for HIV in 2018 when his CD4 count had already fallen to 23—a marker of severe immunosuppression. Two years later, at age 21, he received a diagnosis of acute myeloid leukemia, a cancer of blood-forming cells. This made him the youngest person on record to achieve an HIV cure. In October 2020, he underwent a stem cell transplant using donor cells from someone carrying two copies of a genetic mutation called CCR5-delta32, which disables a receptor that most strains of HIV use to breach and infect human cells. Four months after the initial transplant, he received a boost of additional stem cells. The procedure exacted a toll: he developed multiple infections and graft-versus-host disease, a condition in which the transplanted immune cells attack the recipient's own tissues. In February 2025, more than four years after his transplant, he stopped taking antiretroviral drugs as part of a carefully monitored research protocol. Seventeen months later, tests found no detectable HIV in his blood plasma, no intact viral DNA capable of replication, and no virus that could be cultured in the laboratory.

The second case involves a man from Essen, Germany, who learned he had HIV and AIDS in 2003. Seven years later, at age 51, he was diagnosed with chronic lymphocytic leukemia. In 2020, he received a stem cell transplant from a donor with the same CCR5-delta32 mutation. His situation presented an additional complexity: his HIV was mixed-tropic, meaning some of his virus had evolved to use a different cellular receptor, CXCR4, to enter cells. He also carried hepatitis B, making him the first documented stem cell transplant cure case with both HIV and HBV coinfection. After the transplant, his leukemia went into complete remission. About two years posttransplant, researchers could still detect HIV DNA in his blood cells, but they found no virus capable of replicating. At four years and three months after the transplant, he discontinued antiretroviral therapy—a combination regimen that had dual activity against both HIV and hepatitis B. Fourteen months later, his HIV remained undetectable.

His hepatitis B, however, reactivated. He began taking an antiviral drug that targets HBV but not HIV. He then experienced HBeAg seroconversion, a serological shift that typically signals remission of hepatitis B infection. His new immune system has generated T cells that fight hepatitis B, suggesting he may have achieved what researchers call a functional cure of both infections simultaneously.

These cases matter not because stem cell transplants are a practical path to widespread HIV cure—they are not. The procedures carry substantial risk, are performed only for life-threatening cancers, and cannot be scaled to treat the millions of people living with HIV globally. But they illuminate something fundamental about how the immune system can control or eliminate HIV when given the right genetic tools. Beatriz Grinsztejn, the outgoing president of the International AIDS Society, framed the significance plainly: the transplants themselves remain dangerous interventions reserved for cancer patients, but the insights they generate help researchers understand immune-based strategies that might one day be adapted into safer, more widely applicable treatments. The cases expand the evidence base for what is theoretically possible and point toward mechanisms that could inform the next generation of cure research.