A study was performed by Chinese researchers in the New England Journal of Medicine where they used CRISPR to try to cure a patient's HIV. They did this by using blood cells that were altered to resist AIDS. This was also the first published study where scientists used CRISPR to treat a disease where the DNA that was changed was restricted to that person only. They tested this on a 27-year-old man who had HIV. He needed a blood stem cell transplant in order to treat cancer. In two prior cases, two men were cured of both diseases by transplants from donors who had a gene mutation that actually prevented HIV from ever entering the cells.
Because donors with this resistance to HIV are rare, these Chinese researchers tried to "edit" the genes in order to imitate this mutation. Although this transplant didn't cure the mans HIV, it did put him in remission and the genes that were "edited" were still working even 19 months later. Of course, scientists need to continue to work on this to make gene editing more efficient, but one of the upsides to this gene-editing technique was that in multiple different tests, it was shown that gene-editing didn't have any unwanted effects on any other genes.
This study shows how big of an advancement CRISPR could be in curing and preventing diseases if they continue to test it. What I found the most important in this research was that even though the purpose of curing the HIV virus in this particular study didn't work, it showed that it didn't have any unwanted effects on other genes that weren't being edited. If that were the case, it could have led to many more issues with different genes being edited that were never meant to be.