Norwegian Man Cured of HIV via Stem Cell Transplant

In a significant development for HIV treatment research, Norwegian medical teams have reported the second known case of sustained HIV remission following a stem cell transplant from a donor with a rare genetic mutation that confers natural resistance to the virus. The patient, a man in his 40s from Oslo, underwent the procedure in 2020 to treat an underlying blood cancer and has remained free of detectable HIV without antiretroviral therapy for over three years, marking a rare but important step in the pursuit of an HIV cure.

The case builds on the precedent set by the “Berlin Patient” and later the “London Patient,” both of whom achieved long-term HIV remission after receiving stem cell transplants from donors homozygous for the CCR5-delta 32 mutation — a genetic variation that prevents HIV from entering immune cells. In this Norwegian case, the donor was the patient’s brother, who was found to be heterozygous for the CCR5 mutation, meaning he carried one copy of the protective gene variant. While this does not confer complete resistance, it appeared to contribute to the outcome when combined with the transplant procedure and the patient’s specific clinical circumstances.

The patient had been living with HIV for over two decades before being diagnosed with acute myeloid leukemia, a fast-growing blood cancer that necessitated intensive chemotherapy followed by allogeneic stem cell transplantation. His brother served as the donor, and the transplant proceeded after standard compatibility testing. Although the donor was not a full match for the CCR5-delta 32 trait associated with the most well-documented cases of HIV cure, researchers noted that the partial genetic match, combined with the graft-versus-leukemia effect and the reduction of the HIV reservoir during intensive conditioning therapy, may have played a role in suppressing the virus to undetectable levels.

Post-transplant monitoring showed a rapid decline in HIV DNA levels in blood and tissue samples. By 24 months after the procedure, standard tests could not detect replication-competent virus, and the patient voluntarily discontinued antiretroviral therapy under close medical supervision. As of early 2024, more than 36 months after stopping treatment, no viral rebound has been observed, and immune markers remain stable. Researchers emphasize that while these results are encouraging, the case does not yet constitute a proven cure, and further study is needed to understand the biological mechanisms involved.

Allogeneic stem cell transplantation remains a high-risk procedure, primarily reserved for patients with life-threatening hematologic malignancies due to the dangers of graft-versus-host disease, infection, and treatment-related mortality. It is not considered a viable or ethical approach for HIV treatment alone in individuals who are otherwise healthy and responding well to antiretroviral therapy. Experts stress that the primary value of such cases lies in their ability to illuminate potential pathways toward a cure, such as gene-editing strategies targeting the CCR5 receptor or therapies designed to reduce the persistent viral reservoir.

The CCR5 receptor, which HIV uses to enter CD4+ T cells and macrophages, has long been a focus of cure research. Individuals naturally homozygous for CCR5-delta 32 are extremely rare, particularly outside of Northern European populations, and are largely resistant to HIV infection. Approaches inspired by this natural resistance include efforts to knock out the CCR5 gene in a patient’s own hematopoietic stem cells using gene-editing tools like CRISPR-Cas9, followed by autologous transplantation. Early-phase clinical trials of such strategies are underway, though they remain experimental and face challenges related to efficiency, safety, and long-term effects.

Researchers involved in the Norwegian case, affiliated with Oslo University Hospital and collaborating with Nordic HIV research networks, have submitted detailed findings for peer review. They caution against overinterpretation, noting that each case of apparent HIV remission post-transplant is highly dependent on individual factors, including the timing of treatment, the characteristics of the donor cells, the conditioning regimen used, and the size and stability of the patient’s pre-transplant HIV reservoir. They also highlight the importance of continued surveillance, as late viral rebound — though uncommon — has been documented in other similar cases after extended periods of apparent control.

Globally, only a handful of individuals have demonstrated sustained HIV remission following stem cell transplantation, and all have had underlying conditions necessitating the procedure for reasons unrelated to HIV. The Norwegian case adds to a growing but still limited body of evidence that under very specific circumstances, reducing the viral reservoir and introducing donor cells with impaired HIV susceptibility can lead to prolonged control of the virus without ongoing therapy. However, scientists agree that scalable, safe, and widely applicable interventions will likely require advances in gene therapy, immune-based treatments, or latency-reversing agents rather than reliance on transplantation.

As of 2024, antiretroviral therapy remains highly effective at suppressing HIV and allowing people with the virus to live long, healthy lives when adherent to treatment. The focus of cure research continues to shift toward strategies that could achieve sustained remission without the risks associated with transplant or prolonged analytical treatment interruption. While each new case provides valuable insights, experts agree that the path to a widely accessible HIV cure remains complex and will require further innovation, rigorous testing, and equitable access to emerging therapies.