A63-year-old man, known as the "Oslo patient," has achieved a near-complete cure from HIV after undergoing a stem cell transplant that completely rebuilt his immune system.
What distinguishes this case from similar previous cases is that the transplanted cells did not come from an unrelated donor, but from his older brother, who happened to carry a rare genetic mutation that makes him naturally resistant to AIDS.
This mutation, known as CCR5 delta 32, disables a protein on the surface of immune cells, which the virus typically uses as a gateway to enter and infect cells. The patient's brother was found to carry two copies of this mutation, completely preventing the virus from targeting immune cells. The doctors themselves noted that this was an extremely rare coincidence, as the probability of the brother being a suitable donor is only 25%, while the prevalence of this mutation in the Northern European population is less than 1%. This led the patient to describe his experience as "winning the lottery twice."
The story began with the man being diagnosed with HIV in 2006, and then starting antiretroviral therapy in 2010, which succeeded in reducing the virus to undetectable levels.
But in 2017, he began experiencing severe fatigue, and doctors later diagnosed him with myelodysplastic syndrome, a type of bone marrow cancer. After drug treatments failed to control the cancer, the medical team resorted to a bone marrow transplant.
The ideal option was to find a donor carrying the CCR5 delta 32 mutation, but the search proved fruitless. Therefore, the patient's 60-year-old brother donated his bone marrow, hoping to treat the cancer first. On the day of the operation, the medical team discovered the wonderful surprise: the brother already carried both copies of the required gene mutation.
After the transplant, the patient suffered from a complication known as Graft-versus-Host Disease, in which the newly transplanted immune cells (the graft) attacked his own body tissues (the host), but he was able to successfully overcome this stage thanks to immunomodulatory drugs.
Two years after the transplant, detailed analysis showed that the transplanted cells had completely replaced the old immune cells in the blood, bone marrow, and intestines.
The team was able to collect 65 million immune cells of the type that the virus usually targets, and found them completely free of any virus capable of replicating.
Based on these results, the patient was allowed to stop taking HIV medication, and since then, there has been no sign of the virus returning, even after examining the lymphoid tissue in his intestines, which is considered the main reservoir for HIV in the body. Most remarkably, the newly formed immune cells responded normally to common viruses like the flu, but did not recognize HIV at all, confirming that they had never encountered it before.
Doctors consider this case a potential cure or a long-term, sustainable remission, though they are scientifically hesitant to use the term "complete cure." Practically speaking, this patient no longer needs to take daily medication for life. However, doctors warn that bone marrow transplantation is a highly risky procedure and cannot be applied to the more than 30 million people living with HIV worldwide. Its use is currently limited to patients with severe cancers that already require transplantation. Therefore, the true value of this case lies in its being an important step toward developing easier and less risky functional therapies, such as genetically modified antibodies, with the hope of enabling as many patients as possible to live without medication for longer periods in the future.
