A bone marrow transplant is a medical procedure performed to replace bone marrow that has been damaged or destroyed by disease, infection, or chemotherapy. This procedure involves transplanting blood stem cells, which travel to the bone marrow where they produce new blood cells and promote growth of new marrow.

Bone marrow is the spongy, fatty tissue inside your bones. It creates the following parts of the blood:

• red blood cells, which carry oxygen and nutrients throughout the body

• white blood cells, which fight infection

• platelets, which are responsible for the formation of clots

Bone marrow also contains immature blood-forming stem cells known as hematopoietic stem cells, or HSCs. Most cells are already differentiated and can only make copies of themselves. However, these stem cells are unspecialized, meaning they have the potential to multiply through cell division and either remain stem cells or differentiate and mature into many different kinds of blood cells. The HSC found in the bone marrow will make new blood cells throughout your lifespan.

A bone marrow transplant replaces your damaged stem cells with healthy cells. This helps your body make enough white blood cells, platelets, or red blood cells to avoid infections, bleeding disorders, or anemia.

Healthy stem cells can come from a donor, or they can come from your own body. In such cases, stem cells can be harvested, or grown, before you start chemotherapy or radiation treatment. Those healthy cells are then stored and used in transplantation.

The success of a bone marrow transplant is primarily dependent on how closely the donor and recipient genetically match. Sometimes, it can be very difficult to find a good match among unrelated donors.

The state of your engraftment will be regularly monitored. It’s generally complete between 10 and 28 days after the initial transplant. The first sign of engraftment is a rising white blood cell count. This shows that the transplant is starting to make new blood cells.

Typical recovery time for a bone marrow transplant is about three months. However, it may take up to a year for you to recover fully. Recovery depends on numerous factors, including:

There’s a possibility that some of the symptoms you experience after the transplant will remain with you for the rest of your life.

(Leukapheresis is a laboratory procedure in which white blood cells are separated from a sample of blood. It is a specific type of apheresis, the more general term for separating out one particular constituent of blood and returning the remainder to the circulation.)

Leukapheresis may be performed to decrease a very high white blood cell count, to obtain blood cells from a patient (autologous) or donor (allogeneic) for later transplant into the patient, or to obtain cells for research purposes.

During leukapheresis, a donor is given five shots to help the stem cells move from the bone marrow and into the bloodstream. Blood is then drawn through an intravenous (IV) line, and a machine separates out the white blood cells that contain stem cells.

A needle called a central venous catheter, or a port, will be installed on the upper right portion of your chest. This allows the fluid containing the new stem cells to flow directly into your heart. The stem cells then disperse throughout your body. They flow through your blood and into the bone marrow. They’ll become established there and begin to grow.

The port is left in place because the bone marrow transplant is done over several sessions for a few days. Multiple sessions give the new stem cells the best chance to integrate themselves into your body. That process is known as engraftment.

Through this port, you’ll also receive blood transfusions, liquids, and possibly nutrients. You may need medications to fight off infections and help the new marrow grow. This depends on how well you handle the treatments.

During this time, you’ll be closely monitored for any complications.

When your doctor thinks you’re ready, you’ll have the transplant. The procedure is similar to a blood transfusion.

If you’re having an allogeneic transplant, bone marrow cells will be harvested from your donor a day or two before your procedure. If your own cells are being used, they’ll be retrieved from the stem cell bank.

Cells are collected in two ways.

During a bone marrow harvest, cells are collected from both hipbones through a needle. You’re under anesthesia for this procedure, meaning you’ll be asleep and free of any pain.

Prior to your transplant, you’ll undergo several tests to discover what type of bone marrow cells you need.

You may also undergo radiation or chemotherapy to kill off all cancer cells or marrow cells before you get the new stem cells.

Bone marrow transplants take up to a week. Therefore, you must make arrangements before your first transplant session. These can include:

• housing near the hospital for your loved ones

• insurance coverage, payment of bills, and other financial concerns

• care of children or pets

• taking medical leave from work

• packing clothes and other necessities

• arranging travel to and from the hospital

During treatments, your immune system will be compromised, affecting its ability to fight infections. Therefore, you’ll stay in a special section of the hospital that’s reserved for people receiving bone marrow transplants. This reduces your risk of being exposed to anything that could cause an infection.

Don’t hesitate to bring a list of questions to ask your doctor. You can write down the answers or bring a friend to listen and take notes. It’s important that you feel comfortable and confident before the procedure and that all of your questions are answered thoroughly.

Some hospitals have counselors available to talk with patients. The transplant process can be emotionally taxing. Talking to a professional can help you through this process.