The cutting edge of HIV research has dulled a bit in the last month, when Boston researchers observed the return of HIV in two patients who had become measurably virus-free after undergoing bone marrow transplants.
An unfortunate setback, that wasn't really a setback, the media and certain scientists touted the research as a potential cure for HIV. However, members of the scientific community that understood the research, knew that it was expensive, not-scaleable to large numbers, and might fail to "cure" in even the small numbers of patients it was attempted on.
The patients in Boston underwent bone marrow transplants several years ago for cancer, and had since stopped their powerful anti-retroviral (HIV is a retrovirus) medications, which are typically given to those infected with the virus to keep it in check.
The two Boston-study patients had battled HIV for years. They agreed to stop taking their HIV medications earlier this year to test whether the medicine was holding the infections in check, or hopefully it was the transplant of healthy donor bone marrow cells, resulting in new, uninfected, white blood cells. Both had received transplants after chemotherapy and other treatments had failed to stop the progression of Hodgkin's lymphoma (a cancer of the blood).
The ability of HIV to rebound really demonstrates how persistent, and difficult to cure it is. HIV has an incredible ability to hide in a variety of cell types and locations in the human body, and this experimental trial is proof of its talent.
Personally, I am not surprised at the outcome of this small trial. The idea that large doses of radiation and chemotherapy would kill every infected cell/cell type was maybe a bit optimistic. I absolutely applaud the attempt, and I think a lot will be gained from this research, but those scientists and media touting a "cure" were doing a disservice to science.
This research was based on an earlier event where a man was cured of HIV using the same general method. The Berlin Patient (Timothy Ray Brown) was treated for acute myeloid leukemia by chemotherapy, radiation, and bone marrow transplant. The difference between Brown and the Boston patients was the bone marrow used in Brown's case contained a homozygous delta-32 mutation in the CCR-5 gene. The CCR-5 gene makes the CCR-5 protein which is an important receptor the HIV virus uses to gain entry into white blood cells, and if it is structurally changed (due to the delta-32 mutation) then virus entry is impaired.
|CCR-5 is one of a couple of receptors the HIV virus uses to gain entry into cells.|