Bone Marrow Transplants and Stem Cell Transplants for Cancer Treatment
Where Do Transplanted Stem Cells Come From?
Stem cells for a transplant -- whether from peripheral blood cells or bone marrow -- can come from two places: your body or a matching donor’s body.
Autologous transplants involve stem cells taken from your body before you’ve received chemotherapy and radiation. The stem cells are frozen, then reintroduced to your body after treatment.
Allogenic transplants involve stem cells that come from another person whose tissue type "matches" yours. Most donors are relatives -- preferably and most often a sibling.
To find out if stem cells match, a potential stem cell donor will have his or her blood tested in a process called human leukocyte antigen testing (HLA testing). In those very rare cases where the donor is your identical twin -- and thus a perfect match -- it’s called a “syngeneic transplant.”
Another source of donated stem cells is blood taken from the umbilical cord or placenta after childbirth. Some people choose to store or donate this blood after having a baby instead of discarding it. The process of taking the blood doesn’t pose a risk to the mother or child. However, because only a small amount of blood is in the umbilical cord and placenta, cord blood transplants are generally only used in children or small adults.
Stem cells can also come from what is known as a matched unrelated donor (MUD). Your bone marrow and tissue typing is matched against an unknown donor via a bone marrow registry to find a compatible donor. Doctors will search bone marrow registries if the patient does not have a relative who “matches” their stem cells.