A bone marrow transplant is a medical procedure by which a patient’s diseased bone marrow cells are replaced with healthy cells from a donor or the patient himself. The procedure is performed on people who are afflicted by severe illnesses such as leukemia, lymphomas, certain types of anemia and immune-deficiency diseases. Although a bone marrow transplant does not ensure that the disease will never recur, it generally lengthens the patient’s life as well as increases the quality of life.
The bone marrow transplant can take place from another donor to the patient, or can use healthy cells from the patient to repopulate the bone marrow. Bone marrow is a soft, fatty tissue located inside bones where blood cells are produced and begin their development. It is usually removed under general anesthesia from the rear hipbone of the donor, because of the abundance of marrow in that area. A syringe is used to harvest bone marrow, and it may take more than one bone puncture to retrieve the appropriate amount of marrow, which can be from one to two quarts. This procedure does not cause much pain or discomfort to the donor and the lost marrow is replenished by the body with a few weeks.
Prior to obtaining a bone marrow transplant, the patient must undergo chemotherapy, sometimes combined with radiotherapy, to eliminate most of the diseased blood cells in his body. This process will not only kill all of the unhealthy cells, but will also destroy the marrow cells needed to regenerate blood cells. The patient is essentially left with no immune system to defend him against any of the pathogens in the environment. This is why a bone marrow transplant is required. The bone marrow is injected into the patient through a vein and is naturally taken up by the body into the bones.
It takes several weeks for the implanted marrow to begin regenerating blood cells. During this time, the patient must take any and all measures required to prevent infection by invading pathogens. He must also receive blood cell transfusions to help prevent infection and uncontrolled bleeding. During this recovery period, the patient is in a constant state of discomfort with symptoms similar to a very bad flu. Muscle pains, extreme fatigue, general discomfort, nausea, vomiting, and headache are all symptoms associated with post-transplant patients. Even after the patient is deemed healthy enough to leave the hospital, he will need to return to the hospital on a regular basis for follow-up care. It may take up to a year for the patient’s immune system to fully reconstitute itself after a bone marrow transplant.
Although bone marrow transplants have greatly improved the lives of many people afflicted with life-threatening diseases, they are still considered to be a high-risk procedure. The most frequent complications are post-transplant infections, which may require high doses of medication. However, the worst complication that may occur is graft-versus-host disease. This is a condition where the newly implanted immune system begins recognizing the patient’s body as foreign and attacks it as it would an invading pathogen.
Acute graft-versus-host disease usually occurs within three months of transplant and is often fatal. Chronic graft-versus-host disease may also develop and cause the development of inflammation and fibrosis. Both conditions may be controlled using immunosuppressants, but these can lead to deadly infections. Graft-versus-host disease does not occur in patients who undergo transplants using their own healthy bone marrow.