Bone Marrow Transplant

About Bone Marrow Transplant

Hematopoietic stem cell transplantation, often still called bone marrow transplantation, replaces diseased or damaged blood forming tissue with healthy stem cells. Despite the name, it is not an operation in the usual sense: stem cells are collected from bone marrow, from blood after mobilization, or from umbilical cord blood, and are given intravenously. In autologous transplantation the stem cells of the patient are collected, stored and reinfused after high dose chemotherapy, a common approach for multiple myeloma and some lymphomas. In allogeneic transplantation the cells come from a donor, such as a matched sibling, a matched unrelated volunteer identified through international registries, a partially matched family member in haploidentical transplantation, or cord blood. Allogeneic transplantation is used for acute leukemias, myelodysplastic syndromes, aplastic anemia and inherited conditions such as thalassemia, sickle cell disease and severe combined immunodeficiency. Before transplantation a conditioning regimen of chemotherapy, sometimes with radiation, is given, either myeloablative or of reduced intensity. Matching of HLA tissue types between donor and recipient is critical. Graft versus host disease, in which donor immune cells attack the tissues of the recipient, is the major complication of allogeneic transplantation, while the related graft versus leukemia effect helps eliminate remaining cancer cells. Other risks include serious infections before the new marrow begins working, organ toxicity and relapse. The American physician E Donnall Thomas pioneered the procedure and shared the Nobel Prize in Physiology or Medicine in 1990. CAR T cell therapy is now used for some conditions previously treated with transplantation.