Raising hope that a cure for AIDS is possible, Penn researchers have successfully altered the DNA in immune cells to be HIV-resistant in nine different patients.
“This is the first time genetic changes like this have ever been made in humans — where the DNA code has been permanently changed like this,” said Carl June, a School of Medicine professor, who presented his group’s findings on March 2 at an AIDS conference in Boston. Penn Med’s Pablo Tebas was the study’s lead researcher.
For about ten years now, it has been known that a small percentage of the population is born with a mutated CCR5 gene — the gene which encodes a protein that allows HIV to enter cells. People with this mutation have a naturally high resistance to HIV infection. Using this knowledge, the team at Penn was able to alter the DNA code in non-resistant genes.
“The goal is to try to convert people to be HIV-resistant so that they don’t have to be on drugs every day,” June said.
Nine volunteers with HIV donated their blood to the laboratory where the Penn research team modified specific T cells — the immune cells that are infected by the virus — to be HIV-resistant. Afterward, the researchers returned the blood to the patients through blood transfusion.
The HIV-resistant cells have been lasting since the first person was treated in July of 2009. So far, the procedure has resulted in no negative side effects. One patient still needs to be treated before the Phase I trial will be considered complete.
Although all the resistant T cells are made at Penn, some of the patients have been treated at the Jacobi Medical Center in New York, the University of California in Los Angeles and the University of California at San Francisco.
“There are slight differences in the patients enrolled, and the good thing is that it’s been possible to do it at more than one place — it’s not just a boutique thing,” June said.
The idea for the treatment stemmed from a rare case known as the “Berlin patient.” The Berlin patient is a man who was HIV positive and diagnosed with leukemia. He was given a bone marrow transplant from a donor who had the HIV-resistant gene. Three and a half years later, he appears to be cured of both leukemia and HIV, June said.
June explained that the long-term goal is to achieve similar results in patients without having to do a bone marrow transplant.
After Phase I is complete, the next trial would be to test the procedure with infusion therapy, which works by putting treatment directly into the blood stream in cancer patients. If successful, the amount of HIV-resistant cells in the patient will increase.
The idea is that “every person could be a donor for themselves,” eventually reducing the need for patients to take medicine every day, June said.
Though the results do not imply a cure, “this is probably the best candidate right now for a way to have someone actually get cured of HIV,” June added. “It was unthinkable a couple of years ago that there would be a way to do this.”
