The researchers created HIV-resistant stem cells, which they transplanted into the patient, where they survived for more than a year. Although the therapy did not reduce the level of HIV virus in the patient, no unintended genetic alterations were seen - one of the main areas of concern in genome editing.
'This is an important step towards using gene editing to treat human disease,' said Dr Fyodor Urnov, an expert on genome editing from University of California, Berkeley who was not involved in the study. 'Because of this study, we now know that these edited cells can survive in a patient, and they will stay there,' he told Nature News.
The team of scientists from Peking University Stem Cell Research Centre in Beijing, China, developed their approach to mimic the effects of a naturally occurring gene mutation that makes an individual resistant to HIV infection. The gene, CCR5, is responsible for making a protein that the HIV virus uses to get inside cells.
Three HIV patients are reportedly free of the virus after receiving stem cell transplants from donors with the protective mutation (see BioNews 990). However, as the mutation is rare, the team instead took stem cells from healthy donors and used genome-editing technology to delete the CCR5 gene. The edited stem cells were transplanted into the patient, as part of his cancer treatment.
The study is in marked contrast to the widely condemned work by Chinese scientist, Dr He Jiankui, who last year announced he had used genome-editing in human embryos to produce 'HIV-resistant' babies (see BioNews 977). One key difference of the current research is that the mutations were corrected in select adult cells, which would not alter the germline.
The edited cells persisted in the patient's blood during the 19-month study. However, only five to eight percent of the patient's total stem cells contained the protective edit, so the level of HIV was not significantly reduced, although the cancer was in remission.
Professor Deng Hongkui who led the study told CNN that improving the efficiency of genome editing and optimising the transplantation procedure should accelerate the transition to clinical applications. 'The goal of a functional cure for AIDS is getting closer and closer,' he concluded.
The study was published in The New England Journal of Medicine.