ABSTRACT
Bone marrow transplantation has evolved over a period of 50 years. Laboratory observations and animal studies defined the essentials of transplantation biology. The first attempts to transfer these studies to patients met with little success. The definition of the complexities of the human leukocyte antigen (HLA) system made it possible to select compatible sibling donors and more recently unrelated donors. Transplantation of stem cells form marrow, blood, or cord blood is now the treatment of choice for a variety or hematological and genetic diseases. Transplantation using less toxic preparative regimens to induced mixed chimerism makes possible and application to autoimmune diseases. Laboratory and clinical research directed toward induction of tolerance and elimination of malignant cell point the way to a wider application of hematopoietic cell transplantation in the next decade.