CMedEd > Autologous Bone Marrow & Peripheral Blood Stem Cell Transplantation
Autologous Bone Marrow & Stem Cell Transplantation
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What is a stem cell?
Stem cells are immature, blood-forming cells that are found mostly in your bone marrow. Bone marrow is the soft, spongy tissue inside your bones where blood cells are produced. Stem cells rapidly divide and multiply in the bone marrow and eventually produce mature red blood cells, white blood cells, and platelets. When these mature cells enter your bloodstream, some stem cells may get into the bloodstream as well. These stem cells in the bloodstream are called peripheral blood stem cells.
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- Red blood cells carry oxygen from the lungs to all parts of your body and remove carbon dioxide. When your body does not make enough red blood cells, it is known as anemia. Symptoms of anemia include weakness, fatigue, shortness of breath and headache, which occur because your organs are not getting enough oxygen.
- White blood cells fight infections and dangerous substances that invade the body. A low white blood cell count could weaken your body's immune system and its ability to fight disease and infection.
- Platelets help stop bleeding and form a clot on a wound. If your platelet count is low, you may experience easy bruising or bleeding, which can sometimes be severe or life-threatening.
What is a stem-cell transplantation? Why is it performed?
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Certain types of cancer and cancer treatments can destroy your bone marrow and deplete your blood cells. Leukemia, lymphoma, and multiple myeloma can cause your bone marrow to be taken over by a large number of defective and immature blood cells that can interfere with or even shut down normal blood cell production. Doctors perform stem-cell transplantations in these cases to restore your blood cell counts to optimal levels. In treating other types of cancer, doctors often need to give high doses of chemotherapy (and sometimes radiation) to destroy the malignant cells. These treatments can destroy healthy cells and bone marrow as well as malignant cancer cells, because they target all rapidly dividing cells in the blood. Stem-cell transplantation replenishes stem-cells that are destroyed by these treatments, allowing patients to receive high doses of chemotherapy and radiation to treat their cancer. The major new development in the area of transplantation is the introduction of CAR T-cells for the treatment of selected patients with leukemia and lymphoma. Click here to see introduction of CAR T-cells.
What are the different types of stem-cell transplantation?
There are two main types of stem-cell transplantation, depending on where the stem cells come from:
- Autologous: The patient's own stem-cells are harvested before chemotherapy and/or radiation and reinfused into their bloodstream after treatment.
- Allogeneic: Stem cells are taken from a matched donor whose human leukocyte antigens (HLAs) match the patient's. It is important to find a good match to prevent graft rejection, where the patient’s own immune system rejects the transplanted stem cells. It is also important to find a good match to prevent or minimize graft-versus-host-disease (GVHD), where the donor’s immune system attacks the patient's own body systems.
Patients who undergo autologous transplants have a lower risk of infection because their immune system tends to recover more rapidly when receiving their own stem cells. Autologous transplants also have a very low risk of rejection (GVHD). However, for certain types of cancer, autologous transplants may lead to a higher risk of recurrence if there are any cancer cells in the stem-cell specimen. An advantage of allogeneic transplants is that stem-cells from another donor's immune system may actually be able to fight off the cancer cells better than your own. This document focuses mainly on autologous transplants.
Autologous Transplant Process
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- Collection: Your doctor will remove stem cells from either your blood or bone marrow.
- Processing: Your doctor may send your stem cells to a lab to be checked and attempt to remove any malignant cells that may be in the sample. This is called "purging." The lab may perform special maneuvers to change the cell composition.
- Preservation: Your stem cells will usually be frozen and preserved for after your chemotherapy and/or radiation treatments.
- Chemotherapy/Radiation: Your doctor will administer high doses of chemotherapy and/or radiation. Radiation is much less commonly used nowadays.
- Reinfusion: Your stem cells will be thawed (if previously frozen) and reinfused into your bloodstream intravenously. These cells will settle in your bone marrow and help you produce healthy blood cells.
Collection from Bone Marrow
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- Your doctor will use a large needle to "harvest" bone marrow from your hip bone.
- Your doctor will perform this procedure in a hospital and give you general (or spinal) anesthesia to put you to sleep. You may be able to leave within a few hours after surgery, or you may need to stay overnight.
- You may experience soreness or bruising in your lower back or hip for a few days after the procedure. You may also feel tired or weak due to a loss of blood cells.
- For autologous stem cell transplants, collection from bone marrow is rarely used these days. Mostly, stem cells are collected from the blood.
Collection from Blood
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- A doctor will give you subcutaneous shots of a growth-factor drug that causes the bone marrow to make excess stem cells and release them into the bloodstream. In some cases, this will be preceded by a chemotherapy treatment.
- Your blood will go through an apheresis machine from a catheter placed into a vein (usually in the arm or close to the neck). The apheresis machine will separate the stem cells from other blood cells, and these latter cells are then reinfused intravenously back into you.
- Apheresis is usually an outpatient (i.e. not requiring hospitalization) procedure that takes about three to four hours. Your doctor may need to perform this procedure for a few days in a row in order to collect enough stem cells.
Processing Stem Cells
- After collecting your stem cells, your doctor may send them to a lab to be checked. The lab may perform special maneuvers to change the cell composition.
- If the stem cells were taken from your bone marrow, they will be filtered through very fine screens in order to make sure there are no tiny bone or fat particles in the product.
Preservation of Stem Cells
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- The bone marrow or peripheral blood stem cells will be frozen and saved for when you complete chemotherapy and/or radiation. Once frozen, they will last for many months or even years.
- When the stem cells are infused, you may occasionally experience transient side effects due to the preservatives used when freezing and storing the cells. These may include high or low blood pressure, hives or fever. Dimethyl sulfoxide (DMSO) is the main preservative used and may cause you to have strange tastes in your mouth or strange body odors.
Chemotherapy and/or Radiation Treatment
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- Your doctor will give you high doses of chemotherapy and/or radiation to kill the cancer cells in your body.
- Your doctor will also administer these treatments as part of a process known as "conditioning." Conditioning uses chemotherapy and/or radiation to kill the defective or cancer cells in your bone marrow and make room for the new healthy ones. Conditioning also suppresses your immune system to allow the donor's stem cells to engraft. Radiation is much less commonly used nowadays.
- While chemotherapy can be given through a peripheral (i.e. arm) vein, your transplant doctor will usually recommend the placement of a catheter (i.e. a sterile flexible tube and needle placed into a large vein under local anesthesia, usually in the neck or upper chest area). Some of these catheters can be implanted under the skin (i.e. “ports”).
Reinfusion and Recovery
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- After chemotherapy and/or radiation, your doctor and/or a transplant nurse will infuse the collected stem cells into your bloodstream intravenously.
- Reinfusion can be an outpatient procedure with no anesthesia. More commonly, it will take place in a hospital room. After reinfusion, your stem cells will start to settle in your bone marrow and produce healthy blood cells again (engraftment). You can expect your blood cells to return to normal in about two to three weeks after reinfusion and you can expect to remain in the hospital during this time period. Your doctor may give you shots of growth factors for blood forming cells to try to expedite the engraftment process. Your new marrow will produce white cells first, followed by red cells and platelets. In some cases, however, the recovery of blood counts may be delayed, and blood and platelet transfusions may be needed for a longer period of time. These can be given out of the hospital.
- Isolation (i.e. “bubble”) rooms are rarely used nowadays, although hospital room for transplant patients are usually equipped with special air filters to keep microbes, molds and dust away. Visitors are also frequently allowed, although you should ask your doctor about specific policies to be followed in the hospital rooms. It is often possible to visit one of the hospital floors or rooms ahead of time.
- Your new marrow will produce white cells first, followed by red cells and platelets.
- Your doctor may give you antibiotics after reinfusion to prevent you from developing an infection while your white blood cells are still low from conditioning.
- Your doctor may give you blood transfusions to return your red blood cells and platelets to normal levels while you wait for your stem cells to engraft and start producing new blood cells.
Renewed by:
- Paolo Anderlini, M.D.
Professor
Department of Stem Cell Transplantation
Division of Cancer Medicine
The University of Texas MD Anderson Cancer Center
