In healthy people, the body forms platelets and white and red blood cells from stem cells that are produced by the bone marrow. If you have certain diseases, such as leukemia, your bone marrow may not make enough of these immune cells to help you fight off infection. In such cases, your doctor might recommend that you receive a bone marrow transplant. A bone marrow transplant is a procedure in which the healthy immune cells present in a donor's blood are delivered directly into the bloodstream of a patient. There are three different types of bone marrow transplants commonly performed: allogenic, autologous or syngeneic.
Allogenic
If you are a candidate for an allogenic bone marrow transplant, you will receive bone marrow or stem cells that have been provided by a donor. Typically, an allogenic bone marrow donor is a person who is related to the patient by blood, such as a parent or a sibling. To ensure that the donated cells are successfully accepted by the patient, it is important that the donor's tissue type and the patient's tissue type are a close genetic match. If you are unable to find a person within your family who is eligible to donate bone marrow, you might be able to find a donor through the National Marrow Donor Program. In certain cases, some patients will receive bone marrow from a family member whose tissue type does not match the patient's. Such donations carry an increased risk of rejection by the patient's body. Any questions or concerns should be thoroughly discussed with your doctor prior to treatment.
Autologous
If you are an autologous bone marrow transplant candidate, you serve as your own bone marrow donor. Patients who are healthy enough can usually provide a donation of bone marrow or stem cells prior to undergoing medical treatments, such as radiation or chemotherapy, that destroy healthy cells. If you are eligible for an autologous bone marrow transplant, a doctor will remove some of your healthy bone marrow or stem cells---a process called harvesting. Once these cells are harvested, they are frozen until needed.
Syngeneic
If you have an identical twin, you could be a candidate for a syngeneic bone marrow transplant. This process involves harvesting stem cells from the bone marrow of your identical twin sibling, who serves as the donor. Once these cells are harvested, your doctor can deliver them directly into your bloodstream to help you fight off infection. Identical siblings share identical genetic material, which makes such patients ideal for a syngeneic bone marrow transplant.
