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Stem cells are found in bone marrow, and in lesser amounts, in blood. Stem cells 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 70 disorders have been treated with stem cells from cord blood (1).
Parents can now choose to store their newborn baby's cord blood at a private cord-blood bank in case their baby or a family member ever needs it. Or parents can donate the cord blood to a public cord-blood bank so that any genetically matched individual needing treatment has access to it. Prospective parents who are considering these options should have as much information as possible to make an informed decision. Some states require health care providers to discuss options for umbilical cord-blood banking with their patients (2).
How are stem cells used to treat diseases?
Individuals with certain illnesses are treated with chemotherapy and/or radiation that destroys their own stem cells. Following this treatment, they receive a stem cell transplant, usually through a large vein in the chest. The transplanted stem cells make their way to the bone marrow. In the marrow, the stem cells continually make new copies of themselves and produce blood cells that rebuild a healthy blood and immune system.
Transplanted stem cells can come from donated bone marrow (often called a bone-marrow transplant) or peripheral (circulating) blood, as well as from cord blood. In some cases, a person may receive a transplant of his or her own stem cells.
Stem-cell 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. Cord blood is now the most common source of stem cells for children requiring a stem cell transplant. Donated bone marrow is the most common source for adults (3). However, cord blood is increasingly used in adults as well.
What are the advantages of stem cells from cord blood?
Stem cells from cord blood offer some important advantages over those retrieved from bone marrow:
In addition, some studies suggest that cord blood may have a greater ability to generate new blood cells than bone marrow (1, 3). This suggests that a smaller number of cord-blood cells are needed for a successful transplantation.
Are there disadvantages to using stem cells from cord blood?
The biggest disadvantage is that the cord contains only a small volume of blood. This means that the unit has a smaller number of stem cells than may be collected from bone marrow. As a result, there may not be enough stem cells to treat some older children or adults. (Doctors are studying the effectiveness of combining more than one cord-blood unit or expanding the number of stem cells in a unit before transplantation to attempt to solve this problem.)
Stem cells from cord blood may take longer to “take” and start producing blood cells than bone-marrow stem cells. This may be due, at least in part, to the smaller volume of stem cells from cord blood (1). Individuals may be at increased risk of infection until the transplanted stem cells produce sufficient disease-fighting white blood cells.
An individual cannot receive a second transplant from the same donor, should the need arise.
When should parents make arrangements to donate or store their baby's cord blood?
Expectant parents should contact a public or private cord-blood bank at least six weeks before their baby's due date. If the parents choose a private bank, the bank will send them a kit that their health care provider can use to collect the cord blood. A Parent's Guide to Cord Blood Banks provides a complete listing of private banks. The initial cost of a private bank ranges from about $1,700 to $2,000, plus a yearly storage fee of $125 (6).
There is no cost to parents who donate their baby's cord blood to a public bank. However, this option is not available everywhere. The National Marrow Donor Program provides a complete listing of participating hospitals; the program's phone number is (800) 627-7692. Parents who choose to donate their baby's cord blood must complete a lengthy parental health and disease questionnaire. The mother also must have blood tests for diseases such as hepatitis and HIV.
Who should consider storing cord blood in a private bank?
Expectant parents who have a family history of certain genetic diseases, such as severe anemias, immune disorders or some cancers, may want to consider the family benefit of storing cord blood in a private bank. Families can get complete information and counseling from health care providers, including genetic counselors.
How likely is a baby to someday need treatment with his own stem cells?
It is very unlikely that a baby will need a transplant of his own cord-blood stem cells (the chances are estimated at about 1 in 2,700) (2). If a child does require a stem-cell transplant, his own stem cells usually are not the safest or most effective source of stem cells for treatment, especially in cases of childhood cancers or inherited (genetic) disorders. For these reasons, the American Academy of Pediatrics (AAP) considers unwise the private storage of cord blood as biological insurance by families who do not have a history of the disorders mentioned above (7). However, the AAP and many scientists favor the collection and storage of cord blood in public banks to be used for unrelated recipients who urgently need blood cell transplants.
How is cord blood collected?
Cord blood is collected immediately after birth (within 10 minutes of delivery). The process does not interfere with labor or delivery in any way. Cord blood can be collected following a vaginal or cesarean (c-section) delivery.
Hospitals may use slightly different methods to collect the cord blood. Usually the doctor or nurse inserts a needle into a vein in the umbilical cord and drains the blood into a blood bag. This can be done before or after the mother delivers the placenta. The collection process takes less than 10 minutes (4).
Donated cord blood is sent to the laboratory where it is tested for infections, other problems and HLA type. The cord blood is then frozen and stored. Cord blood that is going to be stored for possible family use is shipped to the private bank for processing.
Are there concerns about cord-blood banking?
There are a number of concerns about cord-blood banking. The cord-blood banking industry has been largely unregulated. There are no universal guidelines for collection and storage of cord blood, so there are concerns about quality control.
Many public banks and some private banks now undergo voluntary accreditation through the American Association of Blood Banks or NetCord/FACT (Foundation for Accreditation for Cellular Therapy), leading to more uniform standards (1). The Food and Drug Administration (FDA) also has some regulatory requirements including registration of all cord blood banks, screening of the donor (mother and baby) for communicable diseases, and laboratory practices to prevent contamination (8).
There are also concerns about whether there are adequate amounts of banked donated cord-blood units for those who need them. It is very costly to process and store cord-blood units, which has limited the number of public banks. The Stem Cell Therapeutic and Research Act of 2005 provides funding for a national cord blood program (9). The National Marrow Donor Program has been contracted by the government to operate the nation's cord-blood coordinating center, and it runs a cord blood registry with a network of public cord-blood banks that has an inventory of over 90,000 cord-blood units (4). This law should help more individuals to find a match.
Some ethical issues in connection with cord-blood banking have yet to be resolved. Some questions are:
The 2005 law starts to address some of these issues.
Is cord-blood transplantation still experimental?
Cord-blood stem cell transplants are no longer considered experimental (1, 3). According to a 2005 Institute of Medicine report, studies show that cord-blood stem cells are a suitable alternative to bone marrow or peripheral blood stem cells for the treatment of leukemia, lymphoma, aplastic anemia and inherited disorders of immunity and metabolism (3). However, more studies are needed to find out whether stem cells from cord blood or bone marrow are better for treating specific diseases or individuals of varying sizes.
Cord-blood transplants are still relatively new. In 1988, French researchers performed the first successful stem-cell transplant using cord blood. Stem cells from the cord blood of a newborn were given to a 5-year-old sibling with a severe anemia syndrome that included skeletal defects (Fanconi anemia). Since then, cord blood cells from related and unrelated donors have been successfully transplanted in more than 7,000 individuals worldwide (2).
Several large studies of cord-blood transplants from unrelated donors have suggested that cord blood is an acceptable alternative for patients (children and adults) who do not have a related matched donor. Survival rates have been similar for patients who received cord blood or bone marrow from unrelated donors (10, 11, 12, 13).
Scientists also are investigating whether cord-blood stem cells may develop into cells other than blood cells. This could make it possible to someday use them to treat neurologic disorders such as Alzheimer and Parkinson diseases, multiple sclerosis and spinal cord injuries, as well as other disorders such as diabetes. If cord blood proves successful in treating some of these diseases, the recommendations for cord-blood banking will be expanded.