Bone Marrow Transplantation




What is a bone marrow transplantation?

Bone marrow transplantation (BMT) is a special therapy for patients with cancer or other diseases which affect the bone marrow. A bone marrow transplant involves taking cells that are normally found in the bone marrow (stem cells), filtering those cells, and giving them back either to the patient or to another person. The goal of BMT is to transfuse healthy bone marrow cells into a person after their own unhealthy bone marrow has been eliminated.

Why is a bone marrow transplant needed?

The goal of a bone marrow transplant is to cure many diseases and types of cancer. When a child's bone marrow has been damaged or destroyed due to a disease or intense treatments of radiation or chemotherapy for cancer, a marrow transplant may be needed. A bone marrow transplant can be used to: replace diseased, non-functioning bone marrow with healthy functioning bone marrow (for conditions such as leukemia, aplastic anemia, and sickle cell anemia). replace the bone marrow and restore its normal function after high doses of chemotherapy or radiation are given to treat a malignancy. This process is often called "rescue" (for diseases such as lymphoma, neuroblastoma, and breast cancer). replace bone marrow with genetically healthy functioning bone marrow to prevent further damage from a genetic disease process (such as Hurler's syndrome, and adrenoleukodystrophy). Bone marrow transplantation has risks involved, some of which are life threatening. The risks and benefits must be weighed in a thorough discussion with the bone marrow transplant team prior to the procedure.

What can be treated with bone marrow transplantation?
  • leukemia
  • lymphomas
  • some solid tumors (i.e., neuroblastoma, rhabdomyosarcoma, brain tumors)
  • aplastic anemia
  • immune deficiencies (severe combined immunodeficiency disorder, Wiskott-Aldrich Syndrome)
  • sickle cell disease
  • thalassemia
  • Blackfan-Diamond anemia
  • metabolic/storage diseases (i.e., Hurler's syndrome, adrenoleukodystrophy disorder)
  • cancers of the breast, ovaries, and kidneys.
What are the different types of bone marrow transplants?

There are different types of bone marrow transplants depending on who the donor is. The different types of bone marrow transplant include the following:
  • Autologous bone marrow transplant: The donor is the child him/herself. Stem cells are taken from the child either by bone marrow harvest or apheresis (peripheral blood stem cells) and then given back to the child after intensive treatment. Often the term rescue is used instead of transplant.
  • Allogeneic bone marrow transplant: The donor shares the same genetic type as the child. Stem cells are taken either by bone marrow harvest or apheresis (peripheral blood stem cells) from a genetically-matched donor, usually a brother or sister.
    • Other donors for allogeneic bone marrow transplants include:
      A parent - a haploid-identical match is when the donor is a parent and the genetic match is at least half identical to the recipient.
      An identical twin - a syngeneic transplant is an allogeneic transplant from an identical twin. Identical twins are considered a complete genetic match for a marrow transplant.
      Unrelated bone marrow transplants (UBMT or MUD for matched unrelated donor) - the genetically matched marrow or stem cells are from an unrelated donor. Unrelated donors are found through the national bone marrow registries.
  • Umbilical cord blood transplant: Stem cells are taken from an umbilical cord immediately after delivery of an infant. These stem cells reproduce into mature, functioning blood cells quicker and more effectively than do stem cells taken from the bone marrow of another child or adult. The stem cells are tested, typed, counted, and frozen until they are ready to be transplanted.
Because the stem cells are new, they are able to produce more blood cells from each stem cell. Another advantage cord blood has is that the T-lymphocytes (part of the immune system that causes graft-versus-host disease) are not completely functional this early in the stage of life. Recipients of cord blood transplants have a decrease risk for severe graft-versus-host disease.

Credit: National Institute of Health.
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