Bone marrow is the spongy tissue found inside bones. It contains stem cells that produce the body’s blood cells. A bone marrow transplant, also called a hematopoietic stem cell transplant, replaces unhealthy stem cells that can no longer produce blood cells with healthy cells. Stem cells can be harvested for transplant from bone marrow, the umbilical cord blood or from peripheral blood (the blood that circulates throughout the body).
While commonly called a bone marrow transplant, the procedure can also be called a peripheral blood stem cell transplant or a cord blood transplant, depending on the source of the stem cells.
Allogeneic Bone Marrow Transplants
When you receive someone else’s cells, it is an allogeneic transplant. Allogeneic transplants are used for acute and chronic leukemia, non-Hodgkin’s or Hodgkin’s lymphoma, aplastic anemia, multiple myeloma, myelodysplasia, and several other malignant and nonmalignant disorders. Two alternative transplant methods, cord blood transplants and haplo transplants (see below), are also allogeneic transplants.
Autologous Bone Marrow Transplants
Autologous transplants are the most common and involve receiving your own stem cells. The procedure is used for multiple myeloma, lymphoma, amyloidosis and testicular cancer.
Based on your response to the disease, the physician determines the best time to collect the stem cells. Prior to transplant, stem cells are mobilized, collected and frozen. Specifically, they are mobilized through growth factor called granulocyte colony-stimulating factor (G-CSF) or a combination of chemotherapy and G-CSF. Upon mobilization, the stem cells are collected using an apheresis machine, and then processed and cryopreserved until the patient is ready for the transplant procedure.
For some diseases, like myeloma and testicular cancer, a multiple-planned transplant approach is preferable. Options include:
- Autologous/Autologous Transplant — You have one transplant using his or her own cells, followed by another autologous transplant within three months of recovery of the first transplant. This is usually done in a clinical trial setting.
- Autologous/Allogeneic Transplant — An autologous transplant is followed several months later by an allogeneic transplant.
Cord Blood and Haplo Transplants
If a related or unrelated matched donor cannot be found, alternative transplant options may include a cord blood transplant using the stem cells from donated umbilical cords. This procedure is used more often with children. Another option is a haplo (half-matched) transplant using the stem cells of a donor — usually a sibling, parent or child — who is not a complete match for the patient. These procedures are usually part of a clinical trial.
Finding a Donor
Patients and families often have questions about finding a donor. The BMT and Cellular Therapy Program works with each patient’s family members to screen them for eligibility. If there is no match, a donor search coordinator will review the international Be The Match® registry to identify any potential matches. The process of finding a donor takes approximately four to six weeks for a related donor, and an additional six weeks for an unrelated donor.
Preparing for a Transplant
Additionally, there are treatments patients may need to receive before a bone marrow transplant, including:
- Myeloablative Therapy — High-dose chemotherapy and/or radiation given prior to the blood or marrow transplant is given with the intent to wipe out the patient’s immune system and dysfunctional bone marrow.
- Non-Myeloablative Therapy
Reduced Intensity — Patients receive standard doses of chemotherapy, followed by a blood or marrow transplant. It provides patients with a new immune system, while delivering fewer chemotherapy side effects.