The man was diagnosed with HIV nearly 20 years prior and had HIV-1 subtype B, the dominant strain in Europe and the Americas. He spent about 11 years on various antiretroviral drugs. In 2018, the man developed myelodysplastic syndrome, a rare and unrelated blood cancer where immature blood cells in the bone marrow fail to mature properly.
The only cure for myelodysplastic syndromes is an allogeneic stem cell transplant. After about two years of cancer treatment, doctors began looking for a stem cell donor with a CCR5 gene mutation, which normally blocks HIV from entering the body's cells. They hoped finding a donor with the CCR5 mutation would cure both the cancer and the HIV, but they failed to find such a donor.
Doctors settled on the man's older brother as a match to treat the cancer. On the day of the transplant in 2020, genetic testing found the man's brother also carried the CCR5 mutation, an unexpected discovery. The CCR5 mutation affects about one percent of Europeans.
The man is not the first patient to receive such a transplant, but doctors believe he is the first to get healthy cells from a family member in such a procedure. Two years after the transplant, the man was able to stop his antiretroviral regimen. He no longer has any trace of HIV in his body, and his immune system had been 'completely replaced' by his brother's.
Remaining unknowns include the exact date of the transplant in 2020 and the long-term prognosis and potential side effects for the man post-transplant. The case highlights the potential of stem cell transplants for HIV cure but underscores the rarity and complexity of such treatments.