An HIV infection attacks the immune system of those affected. Although HIV can now be effectively treated and prevented through antiretroviral therapy, there’s still no cure that’s fully applicable and accessible for the general population. That’s why finding a definitive cure remains one of the greatest challenges facing modern medicine. 

Nevertheless, there are cases that offer a glimmer of hope regarding this goal, namely patients who’ve achieved viral remission after undergoing a stem cell transplant to treat haematological cancer. To further our knowledge in this area, the international consortium IciStem, coordinated by IrsiCaixa (a leading research center for research on infections and immunity), has spent over a decade monitoring 40 people with HIV who’ve received this kind of transplant.

Thanks to this and other efforts, what in 2009 seemed to be a unique and isolated case, namely that of the so-called “Berlin patient”, is today a scientific reality that’s becoming more prevalent, as there are now ten people worldwide who’ve achieved remission from HIV. The “Oslo patient” was the latest case published, in 2026 in the journal Nature Microbiology. 

The IrsiCaixa researchers involved in the study, Maria Salgado Bernal and Javier Martínez-Picado, who is also the coordinator of IciStem 2.0, explain the case of the “Oslo patient” in this News from the Lab.

The patient is a 62-year-old man who received a stem cell transplant from his brother, a donor who also carries the CCR5Δ32 genetic mutation. This genetic variation alters the CCR5 receptor, which acts as one of the main “entry points” used by HIV to invade the body. As the patient’s blood and immune system regenerated with the donor’s cells, the virus found its “entry blocked”.

Two years after the transplant, and under strict medical supervision, the patient’s antiretroviral treatment was discontinued. After four years without medication, no replication-competent virus has been detected, in either the blood or the body tissues. Moreover, his immune response to HIV has progressively declined, confirming the absence of an active infection.

Although this kind of stem cell transplant can’t be scaled up as a solution for the wider population due to its high complexity, this success story, together with that of the other nine patients and the rest of the consortium’s patients, provides crucial data for the scientific roadmap. The top priority now is to translate this valuable knowledge into much safer and accessible therapies, such as CAR-T cell technology or gene therapy to directly modify the CCR5 receptor.