bone marrow transplant
The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.
DEFINITION:
- bone marrow transplant
-
The technique of using normal bone marrow to replace malignant or defective marrow in a patient. In allogeneic bone marrow transplantation (BMT), healthy bone marrow is taken from a donor who has a very similar tissue type to the recipient's--usually a brother or sister. In autologous BMT the patient's own bone marrow is used. Either type of BMT should be done only in centers specializing in this procedure.
Because the procedure itself carries certain risks, BMT is used only in the treatment of potentially fatal blood and immune disorders, including severe aplastic anemia, leukemia, severe combined immunodeficiency and inborn errors of metabolism.
In allogeneic BMT, before transplantation, all the recipient's marrow is destroyed by treatment with drugs or radiation. Destroying the marrow kills any cancer cells there.
Next, using general anesthesia, bone marrow is aspirated from the donor's iliac crests and/or sternum. Only 20 to 50 ml is removed, since the transplanted marrow grows quickly to occupy the bone spaces.
After aspiration, the bone marrow is transfused intravenously into the patient. The bone marrow cells find their way through the circulation into the patient's marrow cavities, where they start to grow.
In autologous BMT, bone marrow is taken from the patient (usually someone with a malignant disease) while his or her disease is in remission (not active) and stored by cryopreservation (a tissue-freezing technique). Before freezing, the marrow may be treated in an attempt to eliminate any remaining malignant cells. This method remains investigational for most conditions. If the disease recurs, the stored bone marrow can be thawed and reinfused into the patient, after destroying all his or her bone marrow as in allogeneic BMT.
Infection can be a major problem during the recovery period, and isolation nursing procedures must continue for about four to six weeks until the new marrow is producing adequate numbers of white blood cells.
In allogeneic BMT, the other dangerous complication is the rejection process known as graft-versus-host disease (GVHD). GVHD occurs when lymphocytes in the donor bone marrow recognize their new host (recipient) environment as foreign. Symptoms include rash, jaundice, and diarrhea. Immunosuppressant drugs, such as cyclosporine, prevent and treat rejection.
Complications may continue to arise for long periods after BMT.
Used in 1 Article abstract
Used in 1 Article abstract