Types of Transplants
The primary way to think about bone marrow transplant types is based on whose stem cells are being transplanted.
- Do the cells belong to the patient? That is, are they the recipient’s cells that were removed earlier and are being put back in? This is called an autologous (awe-TALL-uh-gus) transplant.
- Were the cells donated from someone else, called a donor? This is called an allogeneic (ale-oh-jen-AY-ic) transplant.
Autologous: Using the Recipient’s Own Cells
For some diseases, doctors can remove stem cells from a patient and then put these cells back into the patient after he or she undergoes conditioning (receiving chemotherapy, irradiation or both). Patients having an autologous transplant do not need a donor; they are their own donor, in a sense.
Allogeneic: Using Someone Else’s Cells
For some diseases, patients cannot use their own stem cells for a transplant. To have a chance at recovery, they need stem cells donated by someone else who is healthy.
Typically these patients begin the transplant process by trying to identify a relative to be their donor. Siblings are most likely to be a close match for a transplant (based on their HLA type). If you don’t have a relative available who is a match, doctors can search donor registries for someone else who is. Read more about how to find or become a donor.
SCCA's Alternative Donor Program makes it possible for nearly any patient to receive a transplant, even if a matched donor cannot be found. Read more about SCCA's alternative donor program that offers outstanding outcomes.
What’s the Difference to Me?
The type of transplant that may be appropriate for you depends on many factors, including the disease you have, the way your doctor expects your body to respond and the availability of a donor. Your doctor will explain which type is recommended for your individual situation.
For patients, the distinction between an autologous or allogeneic transplant is important mainly for these reasons:
- Donor: For an autologous transplant, you do not need to find a donor because you are the donor. For an allogeneic transplant, you do need a donor.
- Preparation: Some aspects of transplant preparation differ depending on whether you will be getting your own cells or someone else’s. For an autologous transplant, you will undergo stem cell mobilization and collection or bone marrow harvesting. For an allogeneic transplant, preparation will include finding a donor. Then your donor will undergo stem cell mobilization and collection or bone marrow harvesting. Or in the case of a cord blood transplant, doctors will secure stem cells from the donated blood.
- Complications: Some of the potential complications of transplant differ depending on whether you will be getting your own cells or someone else’s.
Different Kinds of Allogeneic Transplants
For patients who are getting someone else’s cells, there are additional distinctions.
- Related vs. unrelated transplant: If your donor is a blood relative, like a sibling, you have a related donor. If not, you have an unrelated (usually anonymous) donor.
- Syngeneic transplant: If your donor is your identical twin, you are having a syngeneic (sin-jen-AY-ic) transplant. Identical twins exactly match each other’s HLA type.
- Mixed chimerism transplant (mini-transplant): For some patients, doctors use low-dose conditioning to weaken, but not destroy, the bone marrow and immune system before infusing stem cells from a donor. Ideally, the transplanted cells engraft and a new immune system develops alongside the patient’s remaining immune system. So the patient has a mixed immune system for a time, and then the transplanted immune system eventually takes over. While a mixed chimerism transplant is intensive, it is in some ways less intensive than a transplant with high- or moderate-dose conditioning (designed to destroy the bone marrow and immune system). This is why a mixed chimerism transplant is sometimes referred to as a mini-transplant. It is also called a nonmyeloablative transplant.