Below are answers to some of the most common questions regarding blood or marrow transplants (BMT's).
What is bone marrow?
The bone marrow is a soft, spongy tissue that fills the insides of the bones. Most blood cells, including red blood cells, platelets, and some white blood cells are produced in the bone marrow and are then released into the bloodstream as they become mature. When your bone marrow is damaged, your ability to fight off infections and disease is impaired. This is called immunosuppression or immune deficiency.
What are the types of blood cells?
All blood cells are produced from a small number of stem cells that are found in their highest concentration in the bone marrow. Peripheral blood stem cells circulate in blood vessels throughout the body. Stem cells represent only about one in a million cells in the bone marrow. The stem cells work like a "blood factory," continually producing all types of new cells.
The red blood cells, or erythrocytes, carry the oxygen necessary for life to all the body's organs and tissues. Each red cell contains hemoglobin, which takes up oxygen as the blood passes through the lungs and releases it in the tissues.
Platelets are cells that circulate in the blood and are essential for the prevention of abnormal bleeding.
The white blood cells, or leukocytes, include the neutrophils, granulocytes, and lymphocytes. These cells play a major role in the body's defense against bacteria, viruses, and fungi.
What is a blood or marrow transplant?
A blood or marrow transplant transfers blood-forming stem cells into a patient, intravenously, and is similar to a blood transfusion. The transplant replaces defective or missing marrow or is used to "rescue" a patient after high dose chemotherapy and/or radiation.
Stem cells, from the bone marrow, the circulating peripheral blood or from umbilical cord blood, are taken from a related donor, an unrelated donor or from the patient.
After the patient receives high doses of chemotherapy and/or radiation therapy, the stem cells are transfused into the patient's bloodstream. The cells find their way naturally to the marrow spaces of the bones. Once there, they begin to grow and multiply, repopulating the bloodstream with white cells, red cells and platelets.
Why do a blood or marrow transplant (BMT)?
There are three reasons to do a BMT:
In the case of bone marrow failure, a BMT replaces absent or abnormal stem cells with functional stem cells allowing production of blood cells and a healthy immune system.
If the patient has cancer, the BMT replaces stem cells that are killed as a side effect of very high dose chemotherapy and radiation therapy given to cure the cancer.
When genetic errors are present, the BMT replaces defective or absent cells in the body that originate in the bone marrow.
What are the types of blood or marrow transplants?
Allogeneic: The stem cells come from a person other than the patient. The stem cells may come from a related donor [sibling(not a twin) or other, close family member], an unrelated donor or umbilical cord blood.
Autologous: The patient receives his or her own stem cells. The advantages of an autologous transplant include decreased transplant-related life-threatening side effects, no risk of graft-versus-host disease and the availability of the donor. The major disadvantage of an autologous transplant is the risk of relapse.
Syngeneic: The stem cells comes from an identical twin.
What diseases are treated with a blood or marrow transplant?
There is a wealth of information available on the Internet about some of the diseases that are treated with a BMT.
Acute Lymphocytic Leukemia (ALL)
Acute Myelogenous Leukemia (AML)
Chronic Lymphocytic Leukemia (CLL)
Chronic Myelogenous Leukemia (CML)
- Juvenile Myelomonocytic Leukemia (JMML)
- Myelodysplastic Syndrome (MDS)
- Brain tumors
- Ewings sarcoma
- Renal Cell Carcinoma
Inherited Metabolic Disorders:
- Adrenoleukodystrophy (ALD)
- Globoid Cell
- Hurlers syndrome
- Maroteaux-Lamy syndrome
- Metachromatic Leukodystrophy (MLD)
- Krabbe's Disease
Other Inherited Disorders:
- Fanconi anemia
- Sickle Cell Anemia
- Epidermolysis Bullosa
Are there age limitations for BMTs?
Upper age limits are dependent upon diagnosis, type of transplant and transplant center. There are no lower age limits, however there are a limited number of pediatric BMT centers.
How does one find an unrelated donor?
Registries of stem cell donors exist to help patients seeking a transplant. Your transplant center can help you find a donor utilizing these registries. For more information contact the National Marrow Donor Program at 1-800-526-7809.
What is HLA typing?
The success of allogeneic transplantation depends on the match between the HLA (human leukocyte antigens) of the donor and the recipient. This is determined by blood tests. The closer the match between the donor and recipient, the greater the chance that the patient's body will accept the graft and there is a reduced risk of graft-versus-host disease.
How do I choose a BMT Center?
In selecting a BMT Center consider the type of disease being treated, the type of transplant and your insurance coverage. Your insurance carrier may have centers of excellence that they recommend. Your physician is also good resource. The National Marrow Donor Program has a booklet with information about centers that do unrelated donor transplants.
How important is an isolation room?
The purpose of isolation is to protect the patient from infectious agents. The type of room you will be in varies by BMT center and type of transplant. Data supports the need for good hand washing for all caregivers as one of the best means to control infections. Certain areas of the country have different endemic infectious agents which can be controlled by air-filtration systems. You need to check with the BMT centers in regards to specific questions. Patients receiving allogeneic (donor) transplants may need more protective measures against infections than those receiving autologous (their own) stem cells.
Is there a good book I can get that will give me a lot of information about blood or marrow transplants?
Blood and Marrow Transplantation, A Patient's Guide to Hematopoietic Stem Cell Transplantation is available from the University of Minnesota Blood and Marrow Transplant program. This book is given to patients during their first visit to University of Minnesota Masonic Children’s Hospital BMT Clinic. Copies may be purchased by calling our referral number at 1-888-601-0787.