Overview
- The man known as Berlin 2 received a stem-cell transplant for acute myeloid leukemia in 2015, stopped antiretroviral therapy in 2018 against medical advice, and has had no detectable HIV for more than six years.
- His donor carried only one copy of the CCR5 Δ32 mutation, and he also had a single copy, indicating that complete CCR5 loss in donor cells is not strictly required for durable remission.
- Researchers propose a graft-versus-reservoir immune response, in which donor cells eliminate remaining host HIV-infected cells, as a key mechanism behind the sustained remission.
- The case aligns with the previously reported Geneva patient who also remained in remission after receiving cells without CCR5 Δ32, while rebounds in two Boston cases underscore that outcomes vary.
- Clinicians emphasize that full transplants are too risky to use as HIV treatment for otherwise healthy people, and the findings are being used to guide safer approaches such as gene editing, immunotherapies, and reservoir-targeting drugs, as reported in Nature.