Stem cell transplantation.

Historically, a variety of hematological disorders of the bone marrow, such as acute leukemia, chronic myelocytic leukemia and severe aplastic anemia, were invariably fatal. In the past two decades, basic and clinical scientists have been able to change this grim reality into a more hopeful outcome by replacing the diseased bone marrow with stem cells from either a family donor or an unrelated volunteer donor with identical human leukocyte antigens (HLA). Because of progress in this field, the initial experience of mainly using sibling donors has now been expanded to the use of either unrelated adult donors or cord blood cells as a source of hematopoietic cells. These approaches have created ethical concerns for donors and families, concerns that need to be discussed and understood by patients, volunteer donors and health care professionals.