Umbilical Cord Blood

Following the birth of a baby, the umbilical cord usually is discarded along with the placenta. However, it is now known that blood retrieved from the umbilical cord is a rich source of stem cells. Stem cells are unspecialized blood cells that produce all other blood cells, including blood-clotting platelets and red and white blood cells. Like donated bone marrow, umbilical cord blood can be used to treat various genetic disorders that affect the blood and immune system, leukemia and certain cancers, and some inherited disorders of body chemistry. To date, more than 45 disorders can be treated with stem cells from umbilical cord blood.

Currently, commercial companies provide services to parents to store their newborn baby’s cord blood. Prospective parents who are considering this option should have as much information as possible to make an informed decision.

What are stem cells and why are they valuable?

Blood stem cells, most often found deep in bone marrow, are the factory of the blood system. They continually make new copies of themselves and produce cells that make every other type of blood cell. Stem cells are the key to successful bone marrow transplantations (BMTs) because they continue to manufacture blood cells indefinitely.

Bone marrow transplants can be lifesaving for people with leukemia (cancer of the white blood cells) and other cancers, or for those with serious blood disorders, such as aplastic anemia, in which the body does not produce enough blood cells. Stem cells can help enhance a person’s blood producing capability and immune system that are impaired through an inherited (genetic) defect or that have been severely damaged or deliberately destroyed by cancer treatments. At present, donated bone marrow is the most common source of stem cells.

What are the advantages of stem cells from cord blood?

Studies suggest that stem cells from cord blood offer some important advantages over those retrieved from bone marrow. For one thing, stem cells from cord blood are much easier to get because they are readily obtained from the placenta at the time of delivery. Harvesting stem cells from bone marrow requires a surgical procedure, usually under general anesthesia, that can cause post-operative pain and poses a small risk to the donor.

A broader range of recipients may benefit from cord blood stem cells. These can be stored and transplanted back into the donor, to a family member or to an unrelated recipient. For a bone marrow transplant to succeed, there must be a nearly perfect match of certain tissue proteins between the donor and the recipient. When stem cells from cord blood are used, the donor cells appear more likely to “take” or engraft, even when there are partial tissue mismatches.

A potentially fatal complication called graft versus host disease (GVHD), in which donor cells can attack the recipient’s tissues, appears to occur less frequently with cord blood than with bone marrow. This may be because cord blood has a muted immune system and certain cells, usually active in an immune reaction, are not yet educated to attack the recipient. A 2000 study found that children who received a cord blood transplant from a closely matched sibling were 59 percent less likely to develop GVHD than children who received a bone marrow transplant from a closely matched sibling.

The use of cord blood may make blood stem cell transplants available more quickly for people who need them. About 30,000 individuals each year are diagnosed with conditions that could be treated with a bone marrow transplant. Approximately 25 percent of these individuals have a relative who is an appropriate tissue match. While suitable donors can be located for many through national bone marrow registries, the process can take months. Donors can be located within 4 months for about 50 percent of patients. It often is more difficult to find a bone marrow match for members of non-white ethnic and racial groups; transplants from cord blood may make timely treatment available for more of these individuals. Banked stem cells from cord blood can be more readily available, and this can be especially crucial for patients with severe cases of leukemia, anemia or immune deficiency who would, otherwise, die before a match can be found.

Cord blood also is less likely to contain certain infectious agents, like some viruses, that can pose a risk to transplant recipients.

In addition, some studies suggest that cord blood may have a greater ability to generate new blood cells than bone marrow. Ounce for ounce, there are nearly 10 times as many blood-producing cells in cord blood. This fact suggests that a smaller number of cord blood cells are needed for a successful transplantation.

In addition, cord blood stem cells offer some exciting possibilities for gene therapy for certain genetic diseases, especially those involving the immune system. Donald Kohn, MD, and colleagues at the Children’s Hospital of the University of Southern California in Los Angeles and the University of California in San Francisco, made the first attempt at gene therapy with cord blood in 1993 in three children suffering from adenosine deaminase (ADA) deficiency, a potentially fatal defect that cripples the immune system. The children, who also receive additional drug treatment, appear healthy to date, even though their blood now carries only a small amount of the gene introduced into their stem cells.

Source: http://www.marchofdimes.com/professionals/681_1160.asp