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:
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.
Bone marrow transplants are performed when a person’s marrow isn’t healthy enough to function properly. This could be due to chronic infections, disease, or cancer treatments. Some reasons for a bone marrow transplant include:
There are two major types of bone marrow transplants. The type used will depend on the reason you need a transplant.
Autologous transplants involve the use of a person’s own stem cells. They typically involve harvesting your cells before beginning a damaging therapy to cells like chemotherapy or radiation. After the treatment is done, your own cells are returned to your body. This type of transplant isn’t always available. It can only be used if you have a healthy bone marrow. However, it reduces the risk of some serious complications, including GVHD.
Allogeneic transplants involve the use of cells from a donor. The donor must be a close genetic match. Often, a compatible relative is the best choice, but genetic matches can also be found from a donor registry. Allogeneic transplants are necessary if you have a condition that has damaged your bone marrow cells. However, they have a higher risk of certain complications, such as GVHD. You’ll also probably need to be put medications to suppress your immune system so that your body doesn’t attack the new cells. This can leave you susceptible to illness.