In another recent test case, gene therapy has scored an additional small, but significant, success. (See Gene therapy kills breast cancer stem cells, boosts chemotherapy.)
It has been widely reported that during the past year a German man with an HIV infection was apparently fully cleared of the infection after receiving blood transfusions, in therapy for an unrelated case of leukemia, from a donor who had a particular genetic mutation affecting immune system cells. Upon investigation, the nature of the mutation was determined. It has now been functionally reproduced and used in experimental trials with other HIV patients.
The mutation affected the CCR5 receptor of T cells, which is used by HIV to infect the cells and compromise the immune system. 15 experimental subjects had T cells removed and treated with a zinc finger nuclease to disable their CCR5 receptor gene. The cells were then reintroduced in the subjects. In some cases, modified cells persisted for up to 6 months. In one case, the subject stopped taking antiretroviral drugs. HIV returned at first, but it eventually dropped to undetectable levels.
Although this is a very preliminary result, and certainly not yet an effective therapy, it seems to show that researchers are on the right track.
This past year, a Berlin man, Timothy Brown, became world famous as the first—and thus far only—person to apparently have been cured of his HIV infection. Brown’s HIV disappeared after he developed leukemia and doctors gave him repeated blood transfusions from a donor who harbored a mutated version of a receptor the virus uses to enter cells. Now, researchers report promising results from two small gene-therapy studies that mimic this strategy, hinting that the field may be moving closer to a cure that works for the masses.
At the Interscience Conference on Antimicrobial Agents and Chemotherapy in Chicago, Illinois, this weekend, researchers reported preliminary results from tests of a novel treatment in 15 HIV-infected people designed to free them from the need to take antiretroviral drugs