Antiretroviral medications are used to treat HIV infection and over the years have become less toxic and easier to take; however, we still cannot cure HIV infection. Patients still have to take medicines every day of their lives. Timothy Brown, the only person – so far – cured of his HIV infection, received a bone marrow transplant because he had leukemia. The bone marrow came from a donor that did not have the co-receptor (CCR5) that HIV uses to infect CD4 cells. CCR5 is a protein on the surface of the CD4 cells that the virus uses, together with the CD4 protein, to enter the cell. It is like a door into the cell; without it, the virus cannot get in and infect the cell. Another co-receptor that HIV may use is CXCR4.
Bone marrow transplants have lots of complications, and you do not want to have one unless you really need it. At the University of Pennsylvania, we are trying to modify CD4 cells of patients with HIV infection to make them resistant to HIV. In order to do that we have been doing two things
- Remove the protein CCR5 from the CD4 cell surface and then putting those cells back into the patient. Because each patient receives his or her own cells there is no risk of rejection, graft versus host, or the complications associated with Bone marrow transplants.
- Attaching a protein (C34) to the CXCR4 receptor to prevent the HIV virus to enter the cell. It turns out that this strategy in the test tube blocks both the virus that uses CCR5 and the ones that use CXCR4.
In the study that we have now open at Penn, we collect CD4 cells from HIV-positive patients who are doing very well on antiretroviral therapy, and have an undetectable viral load. Then, in the laboratory, we treat those cells and add C34 to the CXCR4 making those cells resistant to HIV infection. Once that is done, the modified cells are infused back into the patient. The hope is that these cells will be able to fight against HIV, and because they cannot become infected, they will not be killed by the virus. We also hope that these cells will multiply in the patient.
The purpose of this study is to determine if this procedure is safe, and if it can be an effective weapon to fight the HIV virus. We need your help to conduct this and other studies to figure out a way to cure HIV, or at least to make the immune system of patients capable of controlling HIV on their own, without having to take antiretroviral medicines.
You will receive compensation for travel and for participation in the study.
For more information about participation, please contact Su Kim, CRNP, at 215-349-8092.
– Pablo Tebas, MD, Principal Investigator, University of Pennsylvania Clinical Trials Unit