Scientists at Johns Hopkins University report that the first hybrid woman to receive a cord blood transplant from a rare mutation carrier has been in HIV remission for more than four years. The report was published in the journal cell.
The “Berlin Patient” was the first person to recover from HIV in 2009, and since then two other men – the “London Patient” and “Düsseldorf Patient” have also cleared the virus. All three received stem cell transplants as part of their cancer treatments. The transplanted cells had two copies of the CCR5-Δ32 mutation that prevented HIV from entering the cell.
Cord blood contains stem cells, including hematopoietic, which are precursors of blood cells. Cord blood transplantation is considered as an alternative to bone marrow transplantation, which also includes hematopoietic stem cells. Patients previously treated with HIV have received stem cell transplants from adult donors.
In a new study, scientists transplanted stem cells from umbilical cord blood. A New York City patient with acute myeloid leukemia and HIV was taking antiretroviral drugs to suppress the replication of the virus. In 2017, she had an HIV-resistant stem cell transplant from umbilical cord blood and an adult donor. The therapy targeted both blood cancer and HIV.
Before the transplant, her own immune system was suppressed by chemotherapy. Because of the necessity of this procedure, stem cell transplants are only reserved for HIV patients who need a transplant for other reasons, such as to treat blood cancer.
The transplant was successful and the patient has been free of HIV and leukemia for over four years. The woman stopped taking antiviral drugs against HIV 37 months after the transplant.
Only about 1% of white people have one copy of the CCR5-Δ32 mutation. It is even rarer in other populations. This limits the probability of transplanting stem cells carrying a beneficial mutation to non-European patients: the probability of finding a donor for European patients is 40-70%, compared to about 20% for a hybrid woman in this study. The study demonstrated the importance of an enhanced search for donors with CCR5-Δ32 mutations.