This involved using the gene editing tool CRISPR-Cas9 to delete a gene known as CCR5 from bone marrow stem cells taken from a donor, before transplanting them into the patient, Peking University scientists said in the study.
“After being edited, the cells — and the blood cells they produce — have the ability to resist HIV infection,” lead scientist Deng Hongkui told CNN Friday.
The patient agreed and the experiment was carried out in the summer of 2017. It was the first time CRISPR-Cas9 was used on a HIV patient. In early 2019, a full 19 months after the treatment was administered, “the acute lymphoblastic leukemia was in complete remission and donor cells carrying the ablated CCR5 persisted,” the scientists said in the paper.
But there weren’t enough of them to eradicate the HIV virus in the patient’s body. After transplantation, only approximately 5% to 8% of the patient’s bone marrow cells carried the CCR5 edit, according to the researchers. “In the future, further improving the efficiency of gene-editing and optimizing the transplantation procedure should accelerate the transition to clinical applications,” said Deng.
But he doesn’t see this as a setback.”The main purpose of the study was to evaluate the safety and feasibility of genetically-edited stem cell transplantation for AIDS treatment,” said Deng. According to Deng, this was a success: the scientists didn’t detect any gene editing-related adverse events, even if “more long-term in-depth studies are needed for off-target effects and other safety assessments,” Deng said.
Deng Hongkui remains a strong believer in CRISPR-Cas9. He thinks it could “bring a new dawn” to blood-related diseases such as AIDS, sickle anemia, hemophilia and beta thalassemia and that, thanks to this new technology, “the goal of a functional cure for AIDS is getting closer and closer.”