Developing a Cure
The medical community has not yet found a cure for HIV/AIDS, but a striking case from Berlin may provide valuable insights into potential treatment strategies: Due to a genetic mutation (known as CCR5-delta32), some people do not express chemokine receptor 5 (CCR5), a co-receptor for HIV, on their CD4+ cells. These individuals are naturally resistant to R5 HIV infection. In the Berlin case, a patient with leukemia and HIV received a stem cell transplant from an individual with this mutation.115 Since the stem cell treatment, which occurred several years ago, doctors have not found any evidence of HIV. This finding has prompted further study in an attempt to replicate these results and ultimately develop a cure.
In 2011, Sangamo BioSciences announced a cell-based method for reducing HIV viral load, harnessing the potential therapeutic power of the CCR5 mutation. The process involves the temporary cessation of antiretroviral treatment, the removal of T cells containing the CD4 receptor, and the exposure of these cells to an enzyme to knockout the gene for the CCR5 co-receptor. Following this treatment, the cells are re-introduced into the patient, where they appear to function normally. In preliminary experiments, this method has been found to boost CD4 cell counts in people with HIV and may also be useful for controlling viral load. One HIV-infected patient in these experiments was able to maintain a controlled viral load even without HAART.116
Numerous other investigations have been carried out to devise a cure, including attempts to produce an HIV vaccine. Kang and colleagues recently developed the SAV001 vaccine, which is now undergoing clinical trials. The SAV001 vaccine is made by genetically modifying the virus so that it is no longer pathogenic. From there, the virus undergoes further deactivation via radiation and chemical treatments. Testing this vaccine in clinical trials will take a few years, but if it proves successful, it will represent one of the greatest developments in the history of HIV/AIDS research.