Local News: Wednesday, April 17, 2002
Stem cells may keep MS from advancing
By Liz Kay
Los Angeles TimesStem-cell transplants, first developed to cure blood cancers, may halt the progression of multiple sclerosis, University of Washington researchers reported yesterday.
Most scientists believe multiple sclerosis is an autoimmune disorder — a victim's own immune system attacks nerve fibers in the brain and spinal cord.
People with the disease suffer pain, have difficulty controlling their muscles and experience cognitive problems.
But a study from the UW Medical Center suggests that obliterating a person's immune cells and then growing a new set by using the patient's own stem cells might prevent the disease from getting worse.
Dr. George Kraft, director of the UW Multiple Sclerosis Research and Training Center, presented the study yesterday at the American Academy of Neurology meeting in Denver.
Scientists have known since the 1950s that suppressing the immune system reduces the progression of MS.
But "if that were the end of things, the patient would die" because the absence of a working immune system would leave the way open to infections, Kraft said. The technique has "always been in the back of our minds, but you couldn't get up to a therapeutic level because of the toxicity."
To avoid that problem, the researchers use stem cells. Nearly all cells in the body have a specific function: Blood cells cannot become muscle cells, nerve cells cannot become skin cells, and so on.
By contrast, the cells of an embryo are unspecialized — they can develop into many different types of tissue. Stem cells, which in adults are mostly found in bone marrow, retain that flexibility.
In the research, doctors gave the patients an injection of growth factor to send stem cells out of the bone marrow and into the bloodstream.
The doctors then harvested the stem cells by drawing the patient's blood and filtering it, keeping the stem cells and immune cells that might perpetuate the disease.
"We're trying to prevent the reintroduction of the disease," said Richard Nash, a transplant physician at the Fred Hutchinson Cancer Research Center. He helped develop the procedure.
Once the stem cells are harvested, researchers used radiation, chemotherapy and antibodies to wipe out the patient's immune system.
Finally, the stem cells are reintroduced to the patient's bloodstream, where they turn into new immune-system cells. The level of immune cells recovers within nine days, Nash said.
The researchers, working with transplant physicians in different centers, followed 26 patients for an average of 15 months after the procedure, called autologous stem-cell transplantation. In more than 75 percent of the patients, their disability stopped getting worse, Kraft said.
There is, however, no guarantee that the immune cells won't begin attacking nerve fibers again, he noted.
The procedure has risks. Some patients — about 5 to 10 percent in these studies — have died from infection due to immune-system suppression.