Human Immunodeficiency virus (HIV) is a virus that attacks the body’s immune cells, making the body prone to infections especially the kinds that do not usually affect normal people. According to the World Health Organization (WHO), an estimated 38.41 million people were living with HIV in 2021. Over the years, scientists have made efforts to find a cure. Recently, at least five people have been HIV-free following stem cell transplants, according to research from Oregon Health & Science University. The study’s findings could help scientists go closer to discovering the general cure for the AIDS virus.
HIV Virion Credit: Thomas Splettstoesser
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HIV was undetectable in lymph nodes
In 2009, a stem cell transplant was used to successfully treat the first known case of HIV. Some cancers are treated by stem cell transplants, often known as bone marrow transplants. In Berlin, Germany, a man who had HIV was also identified as having acute myeloid leukemia and underwent a stem cell transplant. Subsequently known as the Berlin patient, he was given stem cells from a donor who had a mutant form of the CCR5 gene; this gene ordinarily produces a white blood cell surface receptor that HIV uses to infect new cells. A CCR5 mutation makes the virus more difficult to infect cells and can increase an individual’s resistance to HIV. Four additional individuals have experienced a similar recovery since the Berlin patient.
The scientists used Mauritian cynomolgus macaques, a nonhuman primate species, in the study. The team had previously shown that these animals can successfully receive stem cell transplants. All eight participants in the trial had HIV, but only four received stem cell transplants using donors who were HIV-negative, and the other half served as the study’s controls and received no transplants. Two of the four patients who underwent transplants were effectively treated for graft-versus-host disease, which is frequently linked to stem cell transplants, and both were subsequently cured of HIV.
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Also uncovered by the researchers was the fact that the systems of the test subjects gradually rid themselves of HIV. First, the researchers noticed that the blood flowing through their arms and legs no longer contained the virus. Next, they were unable to detect HIV in lymph nodes. First to be HIV-free were lymph nodes in the limbs, then lymph nodes located in the abdomen.
Similar techniques have been used by other researchers to attempt to cure nonhuman primates of HIV, but this study represents the first time that HIV-cured research animals have endured for an extended period of time. Four years after the transplant, both are still alive and HIV-free.
Clinical significance
Physicians may benefit from the scientists’ step-by-step observations of HIV eradication as they assess the efficacy of possible HIV treatments. Clinicians could, for instance, concentrate on studying blood drawn from lymph nodes as well as peripheral veins. This information may also assist to explain why some transplant recipients first seemed to be cured, but HIV was later found in some of them.
Conclusion
HIV represents a significant burden in the world today, scientists are expectant as studies continue. These findings show the value of combining pre-clinical research on macaques with human clinical trials to address issues that would be nearly impossible to address otherwise and to pave the way for the eventual treatment of human disease.
References
Wu, H. L., Busman-Sahay, K., Weber, W. C., Burwitz, B. J., Stanton, J. J., Sacha, J. B., & et al. (2023). Allogeneic immunity clears latent virus following allogeneic stem cell transplantation in SIV-infected ART-suppressed macaques. Immunity. Published online May 25, 2023. https://doi.org/10.1016/j.immuni.2023.04.019
