Chemotherapy, radiation therapy, and cancers such as leukemia and lymphoma can destroy bone marrow, which contains stem cells necessary for manufacturing the blood cells needed for the body to stay alive. Bone marrow transplantation consists of two types of transplants, autologous (cells from the patient’s own body) and allogeneic (cells from a donor). Both types work by infusing filtered stem cells into the patient to replace destroyed or diseased bone marrow. Sometimes, the donated cells can even kill cancer cells more effectively than the person’s original immune cells.

