July 27, 2012
Studies detailing three different approaches are offering hope that a cure for AIDS is on the horizon. All involve procedures or treatments that are already in use, but await further research to see if they can deliver as a cure.
Stem-cell transplantation, an expensive procedure with its own risks, was the method used for the only person believed to have been cured of HIV infection. Timothy Brown received the treatment in Germany for leukemia. His physician purposefully chose a donor who carried a rare mutation that made cells resistant to HIV infection. When Brown recovered, he had no detectable virus.
In research presented Thursday to the 19th International AIDS Conference (IAC) in Washington, two other similar cases involved lymphoma patients. The chemotherapy they had received was less aggressive than that given Brown, and more of their immune cells remained. The transplanted cells appear to have tracked down these cells, some of which were HIV-infected, and destroyed them in a reaction called "graft vs. host disease." No HIV could be grown out of one patient's blood 3.5 years later, or from the other patient's blood almost two years later, reported Timothy J. Henrich and Daniel R. Kuritzkes of Harvard Medical School.
A second strategy involved treatment immediately after infection. In a study presented at IAC by Charline Bacchus and Asier Saez Cirion of the Pasteur Institute in France, 14 patients had initiated a standard three-drug HIV treatment regimen within weeks of infection, then stopped taking them three years later on average. After an average of six years off the drugs, the patients still have little or no detectable HIV in their blood.
The patients do have virus in some sleeping immune cells, but not the long-living type. The patients also lack the usual genetic profile of "elite controllers." One theory is that treatment had begun so early the infection did not have enough time to take residence in various tissues.
A third strategy is called "shock and kill" and involves flushing HIV from sleeping cells with an existing cancer drug, destroying the reservoirs of the virus. [PNU editor's note: More information about this approach appears in today's PNU Medical News.]
07.27.2012; David Brown
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