HIV normally uses the CCR5 co-receptor to help it infect immune cells, but the receptor’s Δ32 variant effectively blocks viral entry but a 14-month success story using cord blood containing an HIV-resistance gene variant called CCR5Δ32 means HIV has been cured in a patient.

As reported at the Conference on Retroviruses and Opportunistic Infections, an HIV patient received a blood (iPSC) stem cell transplant for high-risk acute myeloid leukemia and is free of the virus and HIV antiretroviral drug treatment for over a year. The transplanted cells came from two sources: stem cells from a healthy adult relative were used to quickly restore her blood cell population to reduce infectious complications, and umbilical cord blood from an unrelated newborn child was used to provide long-term blood reconstitution. The patient received the transplants after having her own blood cell population, including leukemic cells, destroyed by high-dose chemotherapy. 

Three months after the transplant, tests showed that the patient’s blood cell population was entirely derived from the HIV-resistant cord blood cells. Post-transplant studies could no longer detect HIV by various sensitive assays. The patient eventually stopped taking antiretroviral drugs to suppress her HIV infection, and so far, has been off the HIV drugs for 14 months, with no signs of HIV re-emergence after close follow-up during COVID 19 pandemic—indicating a likely cure, although physicians at this stage prefer to call it long-term remission. She has also been leukemia-free for more than four years.

The investigators concluded that cord blood containing the CCR5Δ32 variant offers a possible cure for both hematological malignancies and HIV and should be considered as a stem cell source when HIV-positive cancer patients need blood stem cell transplants. However, the procedure is considered too risky for HIV-positive patients who otherwise don’t need such transplants.