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HOW STEM CELLS SAVE LIVES Tuesday, May 11, 1999 JANIS HASS Stem cells have been described as the master or parent cells of the body's blood and immune systems. That's because stem cells develop and reproduce red blood cells that supply oxygen, white bloods cells that fight disease and infection, and platelets that help blood clot. Stem cells are found in three places: umbilical cord blood, bone marrow and in the bloodstream. Bone marrow is the most common source of stem cells used in transplants. Harvesting them requires an extensive search for a donor with matching tissue type; the donor then undergoes a painful procedure in which they are removed for possible use in a later operation. Stem cells exist in an adult's bloodstream, but in lower levels than that of a newborn's. But their production can be stimulated in cancer patients by administering the drug G-CSF. The stem cells can then be harvested, frozen and reimplanted into the donor patient to bolster marrow function depleted after intensive chemotherapy treatments for cancer. In comparison, harvesting stem cells from the umbilical cord is quick, painless and relatively inexpensive. Stem cells from cord blood have an important advantage over the other two sources; they are considered "immunologically naive." A newborn's stem cells won't react against a foreign environment as an adult's cells would, says John Akabutu, director of the public cord-blood bank at the University of Alberta in Edmonton. And that means a lower risk of transplant rejection. In transplants using stem cells from the bone marrow, at least five out of six genetic markers must match between the donor and recipient. Using cord blood, as low as four out of six genetic markers need to match, says Dr. Akabutu. So, more matches can be made between unrelated donors and recipients. And, of course, if the medical needs arise for a child with stored cord blood, a perfect match would be waiting, cryopreserved in liquid nitrogen. http://www.GlobeandMail.ca/gam/Health/19990511/HESIDE.html janet paterson 52 now / 41 dx / 37 onset 613-256-8340 / PO Box 171 / Almonte / Ontario / K0A 1A0 / Canada a new voice <http://www.geocities.com/SoHo/Village/6263/> me <[log in to unmask]>