The little boy above is one of more than 30,000 American children and adults diagnosed each year with leukemia, aplastic anemia or other deadly blood diseases. Around the world, tens of thousands of people are stricken with such diseases. Marrow transplants can save many of these people, if only they can find a compatible donor. Right now, more than 3,000 people are looking for a hero who can give them a unique gift of life.
Marrow contains blood stem cells, the basis of the body's blood and immune systems.
Blood stem cells are also found in blood circulating through the body. Transplants replace patients , diseased blood stem cells with healthy cells from a donor. Within a week or two, the transplanted cells begin to reproduce normally, replacing the patient's blood and immune system. These transplants require a precise genetic match between patients and donors. Finding compatible donors for hearts and livers is easier than finding two people similar enough genetically to successfully exchange blood stem cells.