Bone Marrow Transplant
Stem cell transplantation is a procedure that can restore the bone marrow function of individuals who have 
had injury to that site. The function of the bone marrow stem cells is to produce the different types of cells found in the peripheral blood, which include red blood cells, platelets and white blood cells. The bone marrow can be injured by disease or by primary marrow failure. Intensive chemotherapy and radiation can also injure the bone marrow to an extent requiring stem cell transplantation.
Leukemia is a type of cancer of the blood and bone marrow that affects both adults and children. In some circumstances, very high doses of chemotherapy and radiation are required to destroy the malignant (cancer) cells. These high doses of chemotherapy and radiation, however, may also destroy normal bone marrow cells that produce healthy red blood cells, platelets and white blood cells. In the absence of these normal cells, individuals are very susceptible to infections and bleeding. Transplant physicians use stem transplantation so that they can give high doses of chemotherapy and radiation to destroy the cancer cells, but then give back healthy stem cells to restore the function of the bone marrow.
The cells used for transplantation come from three possible sources. This includes bone marrow, peripheral blood and umbilical cord blood. The bone marrow donor can be either a relative, such as sibling or parent, or an unrelated individual with a similar tissue type to the marrow recipient. Donor programs currently exist that help match unrelated donors to individuals that need a stem cell transplant. This requires screening many thousands to millions of people to find an appropriate match. Increasing the number of donors increases the chances that a bone marrow match will be available for individuals in need of transplantation.