Gene-edited stem cells may help cure AIDS

Gene-edited stem cells that are the precursors of blood cells may help cure AIDS patients, a new discovery by Chinese scientists shows, providing new insights into treatment of the serious infectious disease.

In the study, researchers used the stem cells and other progenitor cells that had been gene edited to reduce a protein called CCR5, which serves as a doorway for HIV infection of human cells. The gene-edited cells were transplanted into a patient infected with HIV and with acute lymphoblastic leukemia, a common type of leukemia.

The patient, a 27-year-old Chinese, improved greatly during a 19-month follow-up period and showed almost no symptoms of acute leukemia. In addition, the transplanted gene-edited cells showed resistance to HIV infection during a brief period when the patient stopped taking antiviral drugs, according to the study, published in the New England Journal of Medicine on Sept 11.

Deng Hongkui, a professor in life sciences at Peking University, and a chief researcher involved in the study, said researchers overseas have been trying to use gene-edited stem cells to treat AIDS patients, but the study is the first to have gained initial success in clinical trials of the new methods.

The study started in May 2017 and is continuing, he said.

"The study indicates great potential for gene-editing technologies in the treatment of serious diseases, including AIDS, hemophilia and thalassemia," he said. Thalassemia is an inherited disease in which people have an overload of iron in their bodies.

Previously, scientists from abroad succeeded in treating AIDS patients with transplanted bone marrow cells with a natural genetic mutation in the CCR5 protein that made it immune to HIV infection in the few reported cases. A major reason that such treatment is uncommon is that the genetic mutation is rare among humans, which makes finding the right donor extremely difficult.

A new report involving research led by the University of Cambridge was published in March in Nature. A patient with HIV showed immunity to the virus after receiving bone marrow stem cells from such a donor.

Although researchers achieved successful transplantation and long-term grafts of stem and progenitor cells using the CRISPR gene-editing technique, the efficiency of gene editing using the CCR5 protein is not high, indicating the need for further research into this approach, Deng said.

"The research explored the feasibility and safety of the method," he said. "We need to further improve the efficiency of gene editing and optimize transplantation procedures in our future study, and it is expected that application of the gene-editing technology to clinical use to treat diseases will be accelerated," he said.

Although no adverse results related to the gene editing have been seen in the research, long-term, intensified research is still needed to evaluate the safety of the technology, he said.

The number of people living with HIV worldwide is estimated at 37 million, according to the Joint United Nations Programme on HIV/AIDS.