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Vanderbilt-Ingram Cancer CenterVanderbilt-Ingram Cancer Center


The Transplant Process

What Is Blood and Bone Marrow Transplantation?

The cells and platelets in our blood play a crucial role in the healthy functioning of our bodies. White blood cells, called leukocytes, fight infection. Red blood cells, called erythrocytes, carry oxygen to organs and tissues and then carry away waste products. And platelets help the blood to clot, which controls excessive bleeding.

When these cells become diseased and unable to perform their jobs within our bodies, organs and tissues are affected and the result can often be life-threatening.

The goal of a bone marrow or blood cell transplant is to replace these non-functioning cells with healthy ones. Your condition and specific disease will affect the choice of cells for transplantation, which your doctor will discuss with you. These new cells can be harvested for transplantation from three sources:

  • bone marrow
  • blood circulating in the body, called peripheral blood
  • blood collected from umbilical cords when babies are born, called cord blood

A second decision that must be made for transplantation is the source of the new blood-forming cells – specifically, whether the patient’s own cells will be used or cells will be harvested from an outside source. This decision is based on numerous considerations, including the state of your health and the specific disease you have, and will be determined with the assistance of your physician.

The different types of transplants are described according to the source of the blood cells. They are:

  • autologous, which uses the patient’s own cells, either from the bloodstream or the bone marrow
  • allogeneic, which uses cells from a family member, an unrelated donor or cord blood collected when babies are born
  • syngeneic, which uses cells from an identical twin

In some circumstances, the doctor will recommend a reduced-intensity transplant (RIT), which requires less intensive pre-transplant chemotherapy or radiation therapies. These therapies are used to destroy a patient’s diseased cells and the normal immune system reaction that would work against the transplanted, healthy cells. In contrast, with a RIT this chemotherapy or radiation conditioning regimen is just strong enough to suppress the immune system’s reaction to the new cells.

A RIT usually is done when a patient is not healthy or strong enough to withstand the usual pre-transplant conditioning regimen. These patients most often are older, have compromised organ systems, have had previous transplants or are in poor overall health. Reduced-intensity transplants also are called non-myeloablative transplants and mini-transplants.

To learn more about blood and marrow transplantation, see: