By Susan Kelly M. D., Assistant Professor, Department of Pediatrics
What is cord blood?
When a baby is born, there are a high number of stem cells circulating in the blood that are generally discarded with the placenta. The primary responsibility of these stem cells (what we refer to as umbilical cord blood or cord blood) is to make components of blood -- red blood cells, white blood cells and platelets.
Cord blood can be collected and stored in liquid nitrogen for years and later used for transplants. There are public banks, where mothers can donate the cord blood for use by anyone who needs a transplant (at no charge). There also are private cord blood banks that allow a family to store their baby's cord blood for use by someone in the family (the family pays for its collection and storage). The cord blood units stored in public banks are searchable through a computer registry that's accessible throughout the world.
Cord blood transplants
The first transplant using umbilical cord blood was done in 1988. Since then, thousands of transplants have been performed using cord blood as the source of stem cells.
Why is this important? The first choice for a stem cell donor is usually a perfectly matched sibling (or other matched family member). We look at markers on the cells called HLA types (different than blood type) to see how closely a patient and potential donor match. Matched cells from a family member have a higher chance of taking (engrafting) and cause fewer side effects, such as graft-versus-host disease (GVHD), where the transplanted cells attack their new "host."
However, as families are changing and getting much smaller, the chance of having a fully matched sibling is quite low. Only one in four full siblings will be a match, and half- and step-siblings are almost never a match. The other options for stem cell transplants include finding an unrelated stem cell donor or receiving stem cells from cord blood.
While the bone marrow registry is expanding, the chance of finding a match is less than 50% and much lower for minority patients or patients with mixed ethnicity. Cord blood doesn't need to be matched as closely as other stem cells because they're more naïve immunologically, causing less GVHD. Therefore, a match can be found for a much higher percentage of people.
What is cord blood?
When a baby is born, there are a high number of stem cells circulating in the blood that are generally discarded with the placenta. The primary responsibility of these stem cells (what we refer to as umbilical cord blood or cord blood) is to make components of blood -- red blood cells, white blood cells and platelets.
Cord blood can be collected and stored in liquid nitrogen for years and later used for transplants. There are public banks, where mothers can donate the cord blood for use by anyone who needs a transplant (at no charge). There also are private cord blood banks that allow a family to store their baby's cord blood for use by someone in the family (the family pays for its collection and storage). The cord blood units stored in public banks are searchable through a computer registry that's accessible throughout the world.
Cord blood transplants
The first transplant using umbilical cord blood was done in 1988. Since then, thousands of transplants have been performed using cord blood as the source of stem cells.
Why is this important? The first choice for a stem cell donor is usually a perfectly matched sibling (or other matched family member). We look at markers on the cells called HLA types (different than blood type) to see how closely a patient and potential donor match. Matched cells from a family member have a higher chance of taking (engrafting) and cause fewer side effects, such as graft-versus-host disease (GVHD), where the transplanted cells attack their new "host."
However, as families are changing and getting much smaller, the chance of having a fully matched sibling is quite low. Only one in four full siblings will be a match, and half- and step-siblings are almost never a match. The other options for stem cell transplants include finding an unrelated stem cell donor or receiving stem cells from cord blood.
While the bone marrow registry is expanding, the chance of finding a match is less than 50% and much lower for minority patients or patients with mixed ethnicity. Cord blood doesn't need to be matched as closely as other stem cells because they're more naïve immunologically, causing less GVHD. Therefore, a match can be found for a much higher percentage of people.
In addition, cord blood is stored and readily available. For volunteer bone marrow or peripheral blood donors, it often takes two to four months from the start of a search to getting cells donated for transplant. For patients with very aggressive cancers, or in children with certain metabolic disease, waiting that long may not be an option. In those cases, the fact that you can get cord blood so quickly is a big advantage.
In children, the results from cord blood transplants are very promising. Recently, cord blood has been used more for unrelated transplants then either bone marrow or peripheral blood in the United States. Historically, cord blood transplants have been used primarily for children, because the number of stem cells available in a cord blood unit is too low to remake an adult's blood and immune system. This also has recently changed, as researchers are finding ways of expanding cord blood cells and making cord blood transplants available to patients of all ages.
What's new in cord blood transplants?
At M. D. Anderson, researchers are working on ways to make cord blood transplants available for more people and safer with better results. Some of these studies involve:
• Using novel combinations of chemotherapy given right before the cord blood transplant
• Combining two cord blood units to give higher numbers of cells, and therefore possibly a better chance for cells to take and to grow faster
• "Expanding" cord blood in the lab, making the stem cells duplicate themselves to provide higher numbers of cells for transplant
• Combining cord blood with other types of transplants to try and improve the cancer-fighting ability of the transplant
• Developing other cell therapies; In the basic science labs, cells are being made from cord blood that are engineered to specifically attack B cell leukemias or lymphomas
New trials are opening constantly. Cord blood transplants aren't a perfect solution and have their own set of drawbacks. However, they offer hope to many patients -- more each day.
In children, the results from cord blood transplants are very promising. Recently, cord blood has been used more for unrelated transplants then either bone marrow or peripheral blood in the United States. Historically, cord blood transplants have been used primarily for children, because the number of stem cells available in a cord blood unit is too low to remake an adult's blood and immune system. This also has recently changed, as researchers are finding ways of expanding cord blood cells and making cord blood transplants available to patients of all ages.
What's new in cord blood transplants?
At M. D. Anderson, researchers are working on ways to make cord blood transplants available for more people and safer with better results. Some of these studies involve:
• Using novel combinations of chemotherapy given right before the cord blood transplant
• Combining two cord blood units to give higher numbers of cells, and therefore possibly a better chance for cells to take and to grow faster
• "Expanding" cord blood in the lab, making the stem cells duplicate themselves to provide higher numbers of cells for transplant
• Combining cord blood with other types of transplants to try and improve the cancer-fighting ability of the transplant
• Developing other cell therapies; In the basic science labs, cells are being made from cord blood that are engineered to specifically attack B cell leukemias or lymphomas
New trials are opening constantly. Cord blood transplants aren't a perfect solution and have their own set of drawbacks. However, they offer hope to many patients -- more each day.
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