|Hematopoietic stem cell transplantation refers to a group of procedures which collect stem cells from an individual donor and administers them to an individual with defective bone marrow or immune system. Stem cells are immature cells that are produced in the bone marrow and circulate in small concentrations in the blood. Stem cells are the precursor to white blood cells for immune function, oxygen-carrying red blood cells (erythrocytes), and platelets which facilitate clot formation. In the early 1960's the collection of donor stem cells was done exclusively from the donor's bone marrow, hence the procedure was referred to as bone marrow transplant. Over recent years, advances in medicine have allowed for successful collection and transplantation from bone marrow as well as other sources, such as peripheral blood or placental blood. Consequently the procedure is now generally referred to as "stem cell transplantation" or "hematopoietic stem cell transplantation (HSCT)." This term is used universally to describe any transplantation of the stem cells, regardless of the donor source.|
Four types of hematopoeitic stem cell transplants exist. These include autologous, in which the individual's own stem cells are removed, processed and then returned to the body. A syngeneic transplant refers to transplants in which the donor is an identical twin of the recipient. These transplants are most desirable since the donor marrow and recipient marrow are perfectly matched thus preventing the complication of post-transplant rejection. When the donor is a sibling or parent of the recipient, the transplant is referred to as allogenic. Finally, unrelated donor transplants are those transplants in which the donors are unrelated and have no genetic likeness to the recipient. These donors often require extensive screening, genetic typing and blood typing prior to the transplant procedure to ensure the closest match to the recipient.
Hematopoeitic stem cell transplant were originally performed in the late 1960's for the treatment of certain disorders of the bone marrow such as leukemia, aplastic anemia, Hodgkin's disease and multiple myeloma. More recently, this procedure has been used to help restore the immune system in those with immune deficiency disorders and certain individual's with cancer who have undergone intense chemotherapy treatment.
Source: Medical Disability Advisor