Bone Marrow Stem Cell Transplant

Stem cells are undifferentiated cells in your body that can multiply and transform into various cell types depending on your body's need. Stem cells are found in certain tissues of the body including the bone marrow, the spongy tissue at the center of most bones. Bone marrow stem cells are called hematopoetic cells as they form different types of blood cells, each with unique functions. Besides the bone marrow, hematopoetic stem cells are also present in the bloodstream.

Bone marrow stem cells may become unhealthy or depleted because of cancer, cancer treatment, a blood disorder, or an immune system disorder. This can lead to a deficiency of red blood cells, white blood cells, and platelets.

When red blood cells which carry oxygen to the tissues are reduced, it can lead to fatigue. A lack of white blood cells which are part of the body’s defense system can increase your risk of infections. Deficiency of platelets which are responsible for blood clotting can lead to an increased tendency to bleed.

A bone marrow transplant or stem cell transplant is a procedure to replace the stem cells in your bone marrow and blood with healthy stem cells so that the blood components and normal blood function can be restored.

For a bone marrow transplant, healthy stem cells may be obtained from your own body, a procedure called an autologous transplant, or from a donor, referred to as an allogenic transplant.

Indications

Your doctor may recommend a bone marrow or stem cell transplant in the following cases:

• To replace stem cells that are unhealthy or damaged due to cancer or other disease.
• In preparation for a strong dose of chemotherapy or radiation which can destroy cancer cells more effectively but also damages the bone marrow.
• To treat cancer, as certain transplanted stem cells can directly attack cancer cells.

A bone marrow stem cell transplant can help treat cancerous and noncancerous conditions such as:

• Leukemia
• Lymphoma
• Aplastic anemia
• Multiple myeloma
• Sickle cell disease
• Immune deficiencies

Preparation for a Stem Cell Transplant

Your doctor will perform an evaluation and certain tests to ensure you are fit enough for a bone marrow transplant procedure. Depending on your condition you may need chemotherapy or radiation before your stem cell transplant to reduce the number of cancer cells as much as possible.

To prepare for the transplant a long tube called a catheter is inserted into a large vein in your neck or chest. Also called a central line, this tube remains in place during your treatment and is used to receive the transplanted stem cells, medications, or blood. You will need a caregiver or relative for assistance during your treatment.

Procedure

The procedure for a bone marrow stem cell transplant mainly involves:

• Collecting stem cells from your own body or from a donor
• Preparing for the transplant by receiving treatment to destroy your existing bone marrow and stem cells
• Receiving the transplant to replace your bone marrow stem cells and refresh your immune system

Autologous Stem Cell Transplant

During an autologous transplant, your stem cells are collected or salvaged before receiving a strong dose of chemotherapy or radiation therapy. You will receive medication to mobilize stem cells from the bone marrow to the blood so that a large quantity of stem cells can be obtained. Stem cells are then collected from a vein and stored and will be restored to you once your cancer treatment is over.

Allogenic Transplant Procedure

If your bone marrow is unhealthy or diseased you may need a stem cell transplant from a donor. A suitable donor is carefully identified by performing a Human Leukocyte Antigen, or HLA, blood test to ensure that certain proteins in the donor’s blood match yours closely. Siblings usually make good stem cell donors, but other relatives or unrelated donors may also be considered if the match is good.

Stem cells may be collected from the donor’s blood or from the bone marrow through a procedure called bone marrow harvesting. The stem cells are then stored until you are ready to receive them.

After collecting stem cells from your body or a donor, a strong dose of chemotherapy or radiation is then administered to treat your cancer or destroy your diseased bone marrow.

Following this, the collected stem cells are then injected into your bloodstream and find their way to your bone marrow where they begin producing blood cells.

Post-procedure care

Recovery from a bone marrow transplant is a gradual process during which you will be carefully monitored and undergo multiple tests. Your doctor will check the growth of your stem cells and blood components and will look for any infections that can arise due to the compromised immune system. You will receive antibiotics as a preventive measure, as infections are common and need to be managed effectively. Any side effects resulting from the transplant will also be addressed. Your blood counts will remain low for the first 1-2 weeks, and you may need a blood transfusion to replenish your blood cells and improve your immunity until your stem cells produce a significant number of new blood cells. If you received donor stem cells, your body’s response is evaluated and you may need medications to prevent the transplanted cells from acting against your own tissue, a condition called graft-versus-host disease.

Risks and Complications

Response to bone marrow or stem cell transplants can vary from person to person based on their disease condition, type of transplant, age, and general health. Some patients experience serious complications that require hospitalization. The risks may include:

• Graft-versus-host disease (GVHD)
• Infection
• Failure of stem cell transplant
• Organ damage due to chronic GVHD
• Infertility
• Cataracts
• A new cancer
• Death

Summary

Bone marrow stem cell transplants have improved the outcome for many children and adults suffering from various cancerous and noncancerous disorders. Follow-up care is essential due to the high risk of complications but new research on the horizon offers better treatment methods with reduced risks.