Another important aspect of bone marrow transplantation is finding a suitable donor.  The donor in allogeneic bone marrow transplant is an important person, and great care is taken to identify a suitable donor.
  • Donors are educated so they understand what will happen when marrow is harvested.
  • Donors must undergo several tests and procedures to ensure that they are physically able to safely donate marrow.
  • Immediate family members are tissue or DNA typed first to see if a matched donor can be found within the family.  A matched donor in the recipient’s family is the best donor to have.  Many of the donor’s and recipient’s genes are similar, and there are potentially fewer side effects from treatment.
  • If not one in the recipient’s family is a match, then the transplant coordinator will begin a search for a donor.  There are three additional sources for donors in stem cell transplantation:
  • Unrelated Marrow Donors
  • Unrelated Cord Blood Donors – the cord blood is obtained from the umbilical cord at birth and is rich in stem cells.
  • Haploidentical Donors Parents – are half-matched to their children and may be a suitable donor.

Matched donor — to help minimize the problems that can be caused by the expected immune response, a donor who has similar genetic makeup to you is preferred. Your cells will seem “less foreign” to the transplanted donor cells. Siblings (ie, brothers and sisters who share the same parents as you) are typically the only members of your family that are tested for being a donor because they have a one in four chance of sharing genetic characteristics with you; these characteristics are critical for your body to accept the graft. In general, parents, children, and relatives are not suitable donors since they do not share the same parents, and therefore do not have the same genetic material.

An exception is called a haploidentical transplant, which may be considered under certain circumstances.
Matched unrelated donor — if no siblings are available, or if testing the blood of the siblings does not reveal a match, a matched unrelated donor may be used. The search for an appropriate donor can be accomplished using transplant registries throughout the world.
Mismatched related or unrelated donor — some patients are offered treatment with cells from a partially matched family member (called mismatched related donor). The hematopoietic stem cell product may be specially prepared to minimize the immune response in the patient. Another alternative is to use umbilical cord blood, collected from a healthy newborn infant at the time of delivery; this blood is a rich source of hematopoietic stem cells.