Two monkeys recover from HIV infection, paving the way for widespread human treatment

Stem cell transplantation was used to treat two monkeys infected with simian immunodeficiency virus (SIV), an HIV-related virus that infects 45 primate species. Although some human treatments have already been achieved, the technology has too many side effects to be widely applicable. But with monkeys, the researchers think they understand why the approach worked and what it takes to apply it consistently to humans.

It’s been 14 years since Timothy Ray Brown, known as the Berlin Patient, was cured of HIV, and you may be wondering what’s taking so long. But the Berlin patient also had acute myeloid leukemia and had to undergo a risky stem cell transplant. The stem cells he received were from donors with mutations in stem cells. CCR5 This means that it lacks the receptors that HIV uses to infect white blood cells. Recipients began to produce white blood cells that were less susceptible to HIV. It turns out that the virus died when it lost its ability to infect new cells, and was eventually cured.

Since then, four similar cases have been reported, making it the only known treatment for HIV. If we were still back in the 1980s, when HIV infection was almost certainly a death sentence, such treatments might have been widely adopted despite their enormous cost. However, with the development of highly effective treatments, unless there are exceptional circumstances such as having cancer, most people would rather take lifelong medications than undergo painful, dangerous and unreliable treatments. I prefer to keep drinking A study published in Immunity could be a big step towards changing this situation.

Four out of five people cured by stem cell therapy had graft-versus-host disease (GVHD), in which the donor’s white blood cells attack the host’s cells. The one exception offers hope, but controlling GVHD and understanding its causes is essential for widespread treatment.

Professor Jonah Sasha of Oregon Health and Science University led a team that transplanted stem cells from an SIV-negative donor into four Mauritian cynomolgus macaques with the disease, while the other four were kept as controls. Initially, SIV samples decreased approximately 1,000-fold in all four of her treated macaque monkeys. Two treated monkeys were cured during this process and remained healthy after 4 years, whereas the other two SIVs eventually recovered. Not surprisingly, none of the control groups experienced remission.

Despite the availability of alternatives, a 50 percent success rate is still not a number we want to apply to humans, but comparisons between monkeys in which SIV has disappeared and those in which it has returned have given us a lot about what works. has become clear. Virologists are debating what causes the success of cured humans, and the authors now believe they have many answers.

The authors observed that HIV in the blood from the extremities of the animals first fell below detectable levels, then in the arm and leg lymph nodes, and finally in the abdominal lymph nodes. They suggest that the fact that the entire body was not removed at once explains why some patients did not appear to be HIV-infected, yet the infection recurred, especially when their abdominal lymph nodes were not tested. I think I can explain.

The team found two processes going on at the same time. The transplanted stem cells recognized the HIV-infected cells as foreign to the body and attacked them in a manner similar to techniques widely used to treat leukemia.

CCR5 receptor deficiency helped prevent SIV rebound in cured macaques, but it was not fully functional in the other two macaques. The team behind this paper has also demonstrated that a CCR5-blocking antibody can mimic the effects of transplantation from her CCR5-deficient host, which they hope to use in the future.

“We hope that our findings will make this treatment effective for everyone. Ideally, we hope that it will be possible with a single injection rather than a stem cell transplant.” Sasha said in a statement.

The study is published in the journal Immunity.

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