Chinese scientists use CRISPR tool on HIV patient for the first time

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But doctors offered the Chinese citizen a glimmer of hope: a bone marrow transplant to treat his cancer and an additional experimental treatment to try to rid his system of HIV, according to a new article published in the New England Journal of Medicine.

This involved the use of the CRISPR-Cas9 gene editing tool to delete a gene called CCR5 from bone marrow stem cells taken from a donor, before grafting them onto the patient, said scientists from Peking University.

"After being published, the cells – and the blood cells that they produce – have the ability to resist HIV infection," senior scientist Deng Hongkui told CNN on Friday.

People who carry defective copies of CCR5 are highly immunized against HIV because the virus uses a protein produced by this gene to enter the cells of an infected person. Two men, patients from Berlin and London, were the first in the world to cure HIV after receiving a bone marrow transplant from donors naturally carrying the mutation.

The patient agreed and the experiment was conducted in the summer of 2017. It was the first time that CRISPR-Cas9 was used on an HIV-positive patient. In early 2019, 19 months after treatment administration, "acute lymphoblastic leukemia was in complete remission and donor cells carrying the ablated CCR5 gene persisted," the scientists said in their article.

But they were not numerous enough to eradicate the HIV virus in the patient's body. After transplantation, only about 5% to 8% of the patient's bone marrow cells carried CCR5 editing, according to the researchers. "In the future, improving the efficiency of gene editing and optimization of the transplant procedure should accelerate the transition to clinical applications," said Deng.

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But he does not see this as a setback. "The main objective of this study was to evaluate the safety and feasibility of a genetically engineered stem cell transplant for the treatment of AIDS," said Deng. According to Deng, this has been a success: scientists have not detected any adverse events related to gene editing, even though "longer-term in-depth studies are needed for non-targeted effects and" 39, other security assessments, "said Deng.

According to an article published in Nature in June, the mutation of the CCR5 gene was associated with a 21% increase in the risk of premature death, without anyone knowing why.

The team that conducted the study had previously transplanted modified human CCR5 cells into mice, which made them resistant to HIV. American scientists have conducted similar experiments on humans, with some success, using an older tool for gene editing called zinc finger nuclease.

China has invested heavily in gene modification technology, making biotechnology one of the priorities of its five-year plan announced in 2016. The central government has funded research on a number of global "firsts," including the first use of the gene modification tool. CRISPR-Cas9 in humans in 2016 and the first reported use of gene editing technology to modify non-viable human embryos in 2015.

In December 2018, Chinese scientist He Jiankui created an international tumult after announcing that he had successfully used CRISPR-Cas9 to alter the DNA of two embryos before birth, thus creating the first human being genetically modified in the world.

Deng Hongkui remains a strong supporter of CRISPR-Cas9. He thinks it could "open a new era" for blood-related diseases such as AIDS, sickle cell disease, hemophilia and beta-thalassemia and that, thanks to this new technology, "the goal of a functional curative treatment of AIDS is getting closer ". "

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