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 The term bone marrow transplant may call up visions of cutting out pieces of bone. However, it is really the transfer of stem cells from a donor to a recipient. Mechanically the technique has more in common with transfusion than with organ transplantation.
One of the most common reasons for a bone marrow transplant is that the patient has a leukemia that will not respond to chemotherapy. In these patients, any treatment that removes all of the tumor cells from the marrow also kills the stem cells thus leaving the patient with no ability to make new blood cells
Finding a donor for bone marrow transplantation can be very difficult. The donor must match the patient not only in ABO type as in transfusion, but in hundreds of type characteristics. Remember, when we replace stem cells we are providing a whole new blood system complete with white blood cells that will try to fight anything foreign.
Once a donor is found, the patient's bone marrow and all of the tumor cells are killed leaving an empty marrow.
With the donor under anesthesia, marrow is aspirated (drawn) out of the iliac crest of the pelvis (hip bones). This is only a small portion of the donor's marrow and is soon replaced.
This marrow is filtered and treated to remove bits of bone and other unwanted cells and debris, is transferred to a blood bag, and is infused into the patient's blood, just like a transfusion.
Normal Bone Marrow |
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The donor's stem cells find their way into the patient's empty marrow and begin to produce all of the blood cell types.
Another technique, stem cell transplantation, is providing an alternative for some patients. New technology now allows collection of stem cells by apheresis, rather than the surgical procedure of bone marrow collection.
At the end of a successful bone marrow or stem cell transplantation, the patient's marrow is repopulated with growing cells that are constantly being added to the patient's bloodstream....the normal healthy cycle of cell development, specialization, aging and replacement. |
