Bone Marrow Transplant (BMT)

Bone marrow is the soft, spongy tissue inside your bones that makes blood-forming cells (blood stem cells). These cells turn into blood cells. 

• White blood cells to fight infections.

• Red blood cells to carry oxygen throughout the body.

• Platelets to control bleeding.

Blood-forming cells are also found in the bloodstream and the umbilical cord blood.

A bone marrow transplant is a treatment that replaces unhealthy marrow with a healthy one. It’s also called a blood or marrow transplant (BMT). Healthy stem cells can come from a donor, or they can come from the patient’s own body.

What diseases can BMT treat?

• Blood cancers like leukaemia or lymphoma & multiple myeloma

• Bone marrow diseases like aplastic anaemia

• Other immune system or genetic diseases like sickle cell disease, thalassemia,

• Chronic infections 

• damaged bone marrow due to chemotherapy

• congenital neutropenia, which is an inherited disorder that causes recurring infections

Types of BMT

1. Autologous bone marrow transplant. Stem cells are removed from the patient  before receiving high-dose chemotherapy or radiation treatment. The stem cells are stored in a freezer. After high-dose chemotherapy or radiation treatments, the stem cells are put back in the body to make normal blood cells. This is called a rescue transplant.

2. Allogeneic bone marrow transplant. Stem cells are removed from another person, called a donor. Most times, the donor's genes must at least partly match the patient’s. Special tests are done to see if a donor is a good match. A brother or sister is most likely to be a good match besides parents, children, and other relatives. Matching unrelated donors may also be found through bone marrow registries.

3. Umbilical cord blood transplant. This is a type of allogeneic transplant. Stem cells are removed from a newborn baby's umbilical cord right after birth. The stem cells are frozen and stored until they are needed for a transplant. Umbilical cord blood cells are very immature so there is less of a need for perfect matching. Due to the smaller number of stem cells, blood counts take much longer to recover.

How a Bone Marrow Transplant is Performed?

A stem cell transplant is usually done after chemotherapy and radiation is complete. The stem cells are delivered into the patient’s bloodstream usually through a tube called a central venous catheter. The process is similar to getting a blood transfusion. The stem cells travel through the blood into the bone marrow. Most times, no surgery is needed.

Donor stem cells can be collected in two ways:

• Bone marrow harvest. This minor surgery is done under general anesthesia, which means the process is pain-free. The bone marrow is removed from the back of both hip bones.  

• Leukapheresis. First, the donor is given several days of shots to help stem cells move from the bone marrow into the blood. During leukapheresis, blood is removed from the donor through an IV line. The part of white blood cells that contains stem cells is then separated in a machine and removed to be later given to the recipient. The red blood cells are returned to the donor.

During the procedure

• Stem cells are infused into the body through your central line.

• The transplant infusion is painless. Recipient is awake during the procedure.

• Bone marrow cells that have been frozen and thawed contain a preservative that protects the cells. Just before the transplant, recipient  may receive medications to reduce the side effects the preservative may cause. 

After the procedure

• When the new stem cells enter the body, they begin to travel through the body and to the bone marrow. In time, they multiply and begin to make new, healthy blood cells. This is called engraftment. It usually takes several weeks before the number of blood cells in the body starts to return to normal. 

• In the days and weeks after the transplant, blood tests and other tests are routine to monitor patient’s condition. Medication may be prescribed to manage complications, such as nausea and diarrhea.

• Patient may also need periodic transfusions of red blood cells and platelets until his/her bone marrow begins producing enough of those cells on its own. There is a  greater risk of infections or other complications for months to years after the transplant

Complications associated with a Bone Marrow Transplant

Your chances of developing these complications depend on several factors like your age, your overall health, the disease you’re being treated for and the type of transplant you’ve received.

Complications can be mild or very serious, and they can include:

• graft-versus-host disease (GVHD), which is a condition in which donor cells attack your body

• graft failure, which occurs when transplanted cells don’t begin producing new cells as planned

• bleeding in the lungs, brain, and other parts of the body

• cataracts, which is characterized by clouding in the lens of the eye

• damage to vital organs

• early menopause

• anaemia, which occurs when the body doesn’t produce enough red blood cells

• infections

• nausea, diarrhea, or vomiting

• mucositis, which is a condition that causes inflammation and soreness in the mouth, throat, and stomach