BMT, or blood and marrow transplant, is a procedure to replace unhealthy or destroyed bone marrow with new bone marrow stem cells.
There are three kinds of blood and marrow transplant:
Autologous Transplant
Also called self-donor transplant or rescue transplant, Autologous transplant is when a person's own stem cells are removed before receiving radiation or chemotherapy treatment. Then, the stem cells are put back in the person's body.
Allogeneic Transplant
Allogeneic transplant is when another person's stem cells are removed. Usually the donor and the recipient have the same genetic makeup. Special blood tests are done to make sure a donor and recipient are a good match. At Children's Hospital, we perform four kinds of allogeneic transplant:
- Identical twin donor
- Related donor
- Unrelated donor
- "Mismatched" donor
Umbilical Cord Blood Transplant
Stem cells are removed from a newborn baby's umbilical cord and are stored until needed for transplant.
Blood and Marrow transplantation can be curative for a wide range of disorders, including leukemias, bone marrow failure syndromes, immune deficiency disorders and metabolic diseases. When there is no suitably matched donor within the family, other donor sources are searched.
Recently, umbilical cord blood has emerged as an alternative stem cell source. As experience has grown with the use of cord blood in a variety of transplant settings, known and potential benefits have emerged over conventional transplantation. These include:
- Shorter interval between search initiation and transplant
- Better tolerance of HLA mismatches
- Lower risk of graft-versus-host disease
- Lower risk of viral transmission
- Great potential: long-term storage, expansion
- No donor risk
These must be balanced against potential disadvantages, such as:
- Stem cell dose, especially for older children and adults
- Risk of transmission of genetic disease
- Less cumulative experience
Volunteer marrow donor registries and cord blood banks are simultaneously searched for suitable donors. For many patients, both unrelated donor bone marrow and unrelated cord blood are available as potential options for transplantation. The final choice of stem cell source takes into account a number of factors including:
- Indication for transplant
- Degree of HLA identity
- Availability of the donor
- Urgency of the transplant
- Cell dose in the cord blood unit
Since the first successful use of umbilical cord blood transplantation more than 12 years ago, storage facilities or "banks" have been established worldwide to supply cord blood as an alternative to bone marrow. As the experience in the use of cord blood for transplantation grows, evidence is emerging in support of its use as an alternative source of stem cells where a well-matched family donor is not available. UPMC Children's Hospital of Pittsburgh is taking part in a national trial examining the role of cord blood for stem cell transplantation in children.
