[Reading Science] 'Incurable Disease' AIDS, Third Patient Completely Cured Emerges

The third case of a patient with acquired immunodeficiency syndrome (AIDS), considered an 'incurable disease,' being completely cured has emerged. The method of transplanting stem cells from a donor resistant to the causative agent, human immunodeficiency virus (HIV), into the bone marrow to develop immunity has proven effective once again. However, scientists point out that due to the difficulties of the method, it is unlikely to become widespread.

On the 21st (local time), a research team from the University of D?sseldorf in Germany published a paper in the international journal Nature Medicine reporting the successful treatment of a 53-year-old male patient using this method. Currently, AIDS treatment relies on antiretroviral therapy (ART). However, this only reduces the viral load in the patient to a very low level and maintains it at a level that prevents transmission to others. If the medication is stopped, the virus replicates and spreads again, making it impossible to halt the infection.

The AIDS virus attempting to penetrate immune cells. Stock image.

The research team transplanted stem cells from a donor with a genetic mutation conferring natural immunity to HIV into the bone marrow of this patient, who was diagnosed with acute myeloid leukemia despite having very low HIV levels due to ART since 2013. From 2018, the patient stopped ART, yet HIV has not been detected to date. Over several years following the stem cell transplant, the team collected tissue and blood samples from the patient and consistently found immune cells specifically responsive to HIV. This suggests that a reservoir producing HIV-specific immune cells has been established within the patient’s body. Although HIV DNA and RNA continue to be detected, the virus remains in a non-replicating state. To further understand how the transplanted stem cells function, the team conducted experiments by injecting the patient’s immune cells into a mouse model implanted with a human immune system. The results showed that HIV did not replicate or spread within the mice. Ultimately, the research team discontinued the patient’s ART, and the HIV immune status was maintained thereafter.

The first successful cure of an AIDS patient using this method was confirmed in Berlin, Germany, in 2008. At that time, an AIDS patient named Timothy Ray Brown received a stem cell transplant from a donor with natural immunity while being treated for leukemia. Fortunately, the donated stem cells carried a genetic mutation (CCR5Δ32/Δ32) that prevents HIV from entering cells. As a result, Brown no longer needed ART after treatment and maintained immunity against HIV until his death in 2020. Similar cases were reported in the UK in 2019 and New York in 2022. However, the medical teams involved have not yet established a definitive causal relationship. The international journal Nature reported that the 'D?sseldorf patient' is recorded as at least the third case cured by bone marrow stem cell transplantation.

Scientists regard this as a hopeful result demonstrating that eliminating HIV from the human body is very difficult but not impossible. However, bone marrow transplantation itself can be risky depending on the patient, and finding stem cell donors naturally immune to HIV is also challenging. Therefore, it is considered unlikely that this method will become generalized.