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Scientists report the first use of the CRISPR gene editing tool to try to cure a patient's HIV infection by providing modified blood cells to resist the AIDS virus.
The gene editing tool has long been used in research laboratories and a Chinese scientist was scorned last year when he revealed that he had used it on embryos that had led to the birth of binoculars . The edition of embryos is considered too risky, in part because the changes in DNA can be passed on to future generations.
The Wednesday report of the New England Journal of Medicine, written by various Chinese researchers, is the first published report on the use of CRISPR to treat a disease in an adult, where DNA modifications are limited to that person .
The attempt was successful in some respects, but failed to cure HIV.
Nevertheless, this shows that gene editing is promising and seems so far accurate and safe for this patient, said Dr. Carl June, a genetic expert at the University of Pennsylvania, who wrote a comment in the journal .
"It's really good for the field," said June.
Chinese government subsidies were paid for the research, which was done openly with prior notification on a scientific register and standard informed consent procedures. Some of these steps were missing or called into question in last year's embryo work.
"There are no ethical concerns on this one," June said.
Gene editing permanently modifies DNA, the code of life. CRISPR is a relatively new tool that scientists can use to cut DNA at a specific location.
The new case concerns a 27-year-old HIV-positive man who needed a blood stem cell transplant to treat cancer. Previously, two other men had apparently been cured of both diseases by donor grafts with natural resistance to HIV because they had a gene mutation that prevented HIV from entering the cells.
Since donors are very rare, Chinese scientists have tried to create HIV-like resistance by "modifying" this gene in the laboratory's blood cells to mimic the mutation.
The transplant has put human cancer in remission and HIV-modified cells continue to function 19 months later. But they only comprise 5 to 8% of these blood cells, so they are less numerous than those who can still be infected.
"They have to approach 90% or more, I think, for a chance to cure HIV," June said.
Scientists are testing different methods to make gene editing more efficient and "our results show proof of principle" for this approach, wrote a study leader, Hongkui Deng of the University of Beijing in Beijing, in an email.
A very encouraging result: many tests have shown that the edition had no unexpected effect on other genes.
"One of the concerns is that they could create a Frankenstein cell, that they would touch other genes instead of the intended target," so it was nice that it did not happen, explained June. .
China appears to be making rapid progress in such research and could get its treatments approved sooner than the United States, June said. He has financial ties to some gene therapy companies and is leading another study testing CRISPR for cancer control in the United States. Three patients have been treated to date and some results are expected by the end of this year.
Several other US studies have attempted to control HIV by modifying patients' own blood cells using a different tool for gene editing, zinc finger nucleases. The first test of this type began ten years ago in the United States.
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