Gene Editing Fights HIV
Holly Ortman (11 AM Micro) found an article on the BBC News website about a recent breakthrough in HIV therapy. Long time readers of BIO230 have seen the ups and downs in potential therapies for this disease. Here is Holly’s summary:
More than 1.1 million Americans are infected with HIV while 1 in 6 of those are not aware they are carrying the virus. The number of new infections is steadily increasing by more than 50,000 people per year. HIV has the tendency to progress into AIDS, which approximately 636,000 Americans have died since the beginning of the epidemic (stats from the CDC).
The gay, bisexual, and other men who have sex with men (MSM) remain the highest at risk group. Intravenous drug users and heterosexuals also continue to be affected HIV.
In a small but promising studying, “Doctors used gene therapy to upgrade the immune systems of 12 patients with HIV to help shield them from the virus’s onslaught.” (BBC News, p. 1) The patients’ white blood cells were removed, edited with HIV resistance, and injected back into the patient.
A small percentage, 1%, of the Caucasian population is born with a rare mutation that protects them from HIV. The mutation changes their T-cell structure so the virus cannot attach and multiply. The first patient to be cured of HIV, Timothy Ray Brown, had his immune system destroyed by leukemia treatment and received a bone marrow transplant from a donor with the mutation.
Researchers at University of Pennsylvania changed the 12 patient’s immune systems by editing the DNA inside the T-cells to give them the CCR5-delta-32 shielding mutation. The patient’s T-cells were removed and grown in the laboratory. Once scientists had enough T-cells, about a billion, they incorporated the mutation and infused the cells back into the patient. Even though the researchers had a large number of T-cells, successful incorporation was only about 20%.
After four weeks of being off medication, blood samples were drawn from the patients and T-cell numbers were counted. They found that the number of unchanged T-cells fell whereas the modified T-cells were protected and remained in the blood even after being off medication for one month.
According to Prof. Bruce Levine, director of the Clinical Cell and Vaccine Production Facility at the University of Pennsylvania, this type of gene therapy was very new and had not been successfully used in human trials until now. The purpose was to show that this type of technology was safe and viable. Researchers continue to work on gene therapy to remove the need for expensive daily HIV medications. There is still no idea of how long gene modification will last when it comes to fighting HIV. It isn’t seen as a viable option for initial drug therapy upon diagnosis but very possibly as drug choice later into the disease.