National Cord Blood Program
After a baby is born and the umbilical cord is cut, some blood remains in the blood vessels of the placenta and the portion of the umbilical cord that remains attached to it. After birth, the baby no longer needs this extra blood. This blood is called placental blood or umbilical cord blood: "cord blood" for short.
Cord blood contains all the normal elements of blood — red blood cells, white blood cells, platelets and plasma. But it is also rich in hematopoietic (blood-forming) stem cells, similar to those found in bone marrow. This is why cord blood can be used for transplantation instead of bone marrow.
Benefits of Cord Blood
Cord blood is being used increasingly on an experimental basis as a source of stem cells, an alternative to bone marrow. Most cord blood transplants have been done to treat diseases of the blood and immune system. It has also been used to restore the functional deficiencies of several genetic metabolic diseases. To date, more than 70 different diseases have been treated with cord blood transplants.
Scientists are investigating the possibility that stem cells in cord blood may be able to replace cells of other tissues such as nerve or heart cells. Whether cord blood can be used to treat other kinds of diseases will be learned from this research.
Cord Blood Donations
Cord blood donated to a public cord blood bank provides another source of hope for patients who have no matching donor in their own family, no unrelated donor in bone marrow donor registries that is a suitable match, or no time to find a donor. In those cases, some other source of stem cells must be found.
Bone marrow for unrelated donors has helped solve this problem for several thousand patients. The largest registry in the United States is the National Marrow Donor Program (NMDP), which lists over 5 million volunteers.
Many patients who need a bone marrow transplant, however, cannot find a suitable donor - no relative that matches and no match among volunteer bone marrow donors. According to a report from the U.S. Government Accounting Office (GAO) released in October 2002, 10,000-15,000 people in the U.S. each year have a disease that could be treated with a transplant, but have no HLA-matched related donor. About one-third of these patients try to find an unrelated marrow donor through the NMDP but only 25 percent of them (9 percent of the total who might benefit) actually get a transplant. The odds are even worse for African-American and other ethnic minority groups.
Fortunately, a cord blood transplant does not have to be a perfect match to the patient. Adult bone marrow frequently causes a condition called graft vs. host disease (GvHD), in which the donated cells start to attack the patient’s own cells. This can be a severe and even lethal condition.
However, the cells in cord blood do not appear to be as "immunologically mature" as those in bone marrow. As a result, cord blood transplants are less likely than bone marrow to cause GvHD and, when it does occur, is often less severe.
Because cord blood transplants cause less GvHD, the match to the patient does not need to be perfect. This means that patients who cannot find a perfectly matched bone marrow donor may have a chance to find a suitable cord blood transplant. Patients with rare HLA types, African-Americans and members of other minority groups, therefore, benefit especially from this stem cell resource.
For more information, visit the National Cord Blood Program Web site.