Bone marrow, also known as marrow, is the soft, spongy fatty tissue inside the bones. The bone marrow is the medium for development and storage of most of the body’s blood cells. Stem cells are immature cells in the bone marrow that give rise to all of the different blood cells.
It is the stem cells that are needed in bone marrow transplant.
What is bone marrow transplant (BMT)?
A bone marrow transplant is a procedure performed to replace damaged or destroyed bone marrow stem cells with healthy bone marrow stem cells. The procedure involves extracting the healthy stem cells, filtering those cells, and giving them back, either to the donor himself, or to another person(the recipient). The goal of BMT is to transfuse healthy stem cells into a person, after his or her own unhealthy bone marrow has been treated to kill the abnormal cells.
Why is bone marrow transplant needed?
The goal of a bone marrow transplant is to cure many diseases and types of cancer. Bone marrow transplants may also be needed if the bone marrow has been destroyed by a disease. For some diseases, transplant offers the only potential cure.
A bone marrow transplant can be used to:
Replace diseased bone marrow with healthy, functioning marrow.
Treat a disease that affects the production of bone marrow cells or severe immune system illness.
Regenerate a new immune system that will fight existing or residual leukemia or other cancers not killed by the chemotherapy or radiation used in the transplant.
Replace the bone marrow and restore its normal function after high doses of chemotherapy and/or radiation are given to treat a malignancy. This process is often called rescue (for diseases such as lymphoma and neuroblastoma).
Replace bone marrow with genetically healthy functioning bone marrow to prevent further damage.
The risks and benefits must be weighed in a thorough discussion with the doctors and the specialists in bone marrow transplants, prior to the procedure.
Types of bone marrow transplants
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 BMT include the following:
Autologous bone marrow transplant:
It is defined as “taken from an individual’s own cells”, where the patient has donated stem cells to be used for their own transplant.
Allogeneic bone marrow transplant:
The donor has been selected based on their HLA type (genetic match) and that of the patient. Stem cells are then taken from an HLA matched donor.
Siblings (Matched related donor/ MRD)
Brothers/sisters are the best choice as donors, provided that their HLA type matches with that of the recipient.
Parent/Children (Haploidentical stem cell transplant):
A haploid-identical match is when the donor is a parent and the genetic match is at least half identical to the recipient's.
Unrelated bone marrow transplants (UBMT) or matched unrelated donor (MUD):
The HLA matched marrow or stem cells are from an unrelated donor, who has been found through bone marrow registries.
Umbilical cord blood transplant:
Stem cells are taken from an umbilical cord immediately after delivery of an infant. The stem cells are tested, typed, counted, and frozen until they are needed for a transplant.