Taking 'scissors' to immune cells shows promise against HIV
By Kerry Sheridan, AFP
March 7, 2014, 12:09 am TWN
WASHINGTON--A new gene therapy approach that engineers a person's T cells so that they become resistant to the human immunodeficiency virus has shown early signs of success, researchers said Wednesday.
Also called gene editing, the process acts like molecular scissors to snip off an entry portal for HIV so the virus cannot enter these key immune cells.
Once the cells lack the CCR5 protein, the immune system behaves much the way it does in a rare set of people — about one percent of the population — who are born with a genetic mutation that prevents them from getting HIV.
Experts say the development puts researchers a step closer on the path toward curing AIDS, which has infected nearly 70 million people and killed some 35 million worldwide.
"This study shows that we can safely and effectively engineer an HIV patient's own T cells to mimic a naturally occurring resistance to the virus," said senior author Carl June of the University of Pennsylvania.
Repopulating the Immune System
Researchers re-infused 12 patients with their own modified cells and saw them persist in the body, essentially repopulating their immune systems.
Based on the phase I trial results reported in the New England Journal of Medicine, the technique was described as "generally safe."
One serious adverse event was reported in a patient who was rushed to the emergency room with fever, chills, joint pain and back pain within 24 hours of infusion.
Researchers said the problem was likely a reaction to the study drug. All patients completed the 36-week study and are being monitored for the next 10 years.
The treatment also decreased, at least temporarily, the viral loads of some patients taken off antiretroviral drug therapy, or ART.
The patients were each given a single infusion of about 10 billion cells between May 2009 and July 2012.
A dramatic spike in modified T cells was seen in the patients' bodies a week after the infusion.
Six people were taken off ART for up to 12 weeks, beginning four weeks after infusion, and the other six patients remained on treatment.