'Gene editing' shows positive results against HIV

Gene therapy has been successfully used to improve the immune system of 12 patients diagnosed with HIV. A new clinical trial has successfully edited a gene in the patients' white blood cells that has resulted in the participants reducing their viral load without the need for HIV medication.

Published in the journal 'New England Journal of Medicine', the US trial could lead to treatments for HIV that don't require the use of continued drug therapies. The researchers believe that this is the first published study that made use of gene editing techniques for the treatment of humans.

Researchers from Sangamo BioSciences, California, the University of Pennsylvania and the Albert Einstein College of Medicine, New York, developed technology that allowed them to remove the white blood cells from HIV patients and edit a gene before infusing them back into each trial participant.

According to Carl June, study author and professor at the University of Pennsylvania's Perelman School of Medicine, the new technique shows that changing human T cells is the best way to eliminate the need for ongoing drug therapies for those diagnosed with HIV. He said that is could even help to develop curative approaches for both HIV and AIDS.

The researchers used a new technology called zinc-finger nuclease (ZFN) to edit the CCR5 gene within white blood cells. This resulted in a mutation that only affects around one per cent of people and makes them naturally resistant to HIV. The mutation means that the virus is unable to enter immune cells.

Four weeks after infusion of the altered T cells, six of the 12 patients were taken off their HIV medication for a period of 12 weeks. It was found that four of the patients' viral loads fell during this time, with one patient showing no trace of HIV after the treatment. It was later found that this patient had one natural copy of the gene mutation.

Mr Hune said: "This study shows that we can safely and effectively engineer a HIV patient's own T cells to mimic a naturally occurring resistance to the virus, infuse those engineered cells, have them persist in the body, and potentially keep viral loads at bay without the use of drugs."