Cord blood, however, is a rich source of stem cells. Stem cells are unspecialized cells that produce all blood cells. These include:

• Platelets, which are needed for blood clotting

• Red blood cells, which transport oxygen to the cells

• White blood cells, which help fight disease

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, 2).

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 thier patients (3).

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 (4). 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:

• Safe, easy collection: Collecting stem cells from cord blood poses no risk to mother or baby. Individuals who donate bone marrow must undergo a surgical procedure with general or spinal anesthesia. They may experience postoperative pain, and have a small risk of serious complications. Individuals who donate stem cells from blood must undergo several injections (shots) that stimulate release of stem cells into blood, occasionally causing bone pain and serious complications (4). 

• More matches: For a bone-marrow transplant to succeed, there must be a nearly perfect match of certain tissue proteins (called human leukocyte antigens or HLAs) between the donor and the recipient. Family members, such as siblings, are most likely to be a tissue match. However, only about 30 percent of individuals requiring a stem-cell transplant have a relative that is an appropriate tissue match (4). 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. This means that more individuals may be able to find an appropriate match using cord blood.

• Faster availability: Many individuals who do not have an appropriately matched family member can find a matched donor through national bone-marrow and cord-blood registries. It often takes at least two months to locate an appropriate bone- marrow donor compared to about two weeks for a cord-blood unit (5). The banked cord-blood cells also are available almost immediately. This can be crucial for patients with severe disorders who might die before an appropriate bone marrow donor can be found and complete the donation process.

• More ethnic diversity: Members of non-white ethnic and racial groups often find it more difficult to find a match through a bone-marrow registry because there are fewer registered potential donors from non-white groups. The increasing use of cord-blood cells may make timely treatment available for more of these individuals.

• Reduced risk of graft vs. host disease (GVHD): GVHD is a potentially fatal complication, in which donor cells attack the recipient's tissues. This complication appears to occur less frequently with cord blood than with bone marrow, possibly because cord-blood cells are immature and may lack the ability to attack the recipient (1, 4). 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 (6).

• Fewer infections: Cord blood is less likely to contain viruses that can pose a risk to transplant recipients (4).

In addition, some studies suggest that cord blood may have a greater ability to generate new blood cells than bone marrow (1, 4). 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 $1,100 to $1,750, plus a yearly storage fee of $115-125 (1).

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. In some cases, parents may have to pay for these tests if their insurance does not cover them.

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) (3). 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 (5).

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 similar organizations, leading to more uniform standards (1). The Food and Drug Administration (FDA) is currently developing licensing procedures for cord blood, which should further improve quality control.

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. A new law, the Stem Cell Therapeutic and Research Act of 2005, provides funding to increase the number of banked cord-blood units, and encourages donations from genetically diverse populations (8). This law should help more individuals to find a match. The law also links all cord-blood and bone-marrow banks so that doctors and patients have a single easy-access point to search for the best possible stem-cell match. This single database also will improve studies on the outcomes of patients who undergo stem-cell transplants.

• Some ethical issues in connection with cord-blood banking have yet to be resolved. Some questions are:
  How is informed consent obtained from parents before harvesting cord blood?

• How should the obligation to notify parents and donor-children of the results of medical testing for infectious diseases and genetic information be handled?

• How are privacy and confidentiality maintained?

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, 4). 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 (4). 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 about 6,000 individuals worldwide (4).
 
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 (9, 10, 11, 12). 

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.


References
1. Moise, K.J. Umbilical Cord Stem Cells. Obstetrics and Gynecology, volume 106, number 6, December 2005, pages 1393-1407.

2. National Cord Blood Program. Cord Blood Q&A. New York Blood Center, accessed 6/26/06.

3. American College of Obstetricians and Gynecologists (ACOG). Umbilical Cord Blood Banking  ACOG Committee Opinion, number 399, February 2008.

4. Committee on Establishing a National Cord Blood Stem Cell Bank Program. Cord Blood: Establishing a National Hematopoietic Stem Cell Bank Program. Institute of Medicine, National Academies Press, 2005.

5. National Marrow Donor Program. Cord Blood FAQs. Updated 10/05, accessed 6/26/06.

6. Rocha, V., et al. Graft-Versus-Host Disease in Children who Have Received a Cord-Blood or Bone Marrow Transplant from an HLA-Identical Sibling. New England Journal of Medicine, volume 342, number 26, June 22, 2000, pages 1846-1854.

7. American Academy of Pediatrics (AAP). Policy Statement: Cord Blood Banking for Potential Future Transplantation. Pediatrics, volume 119, number 1, January 2007.

8. Stem Cell Therapeutic and Research Act of 2005. Public Law 109-129, December 20, 2005.

9. Rocha, V., et al. Comparison of Outcomes of Unrelated Bone Marrow and Umbilical Cord Blood Transplants in Children with Acute Leukemia. Blood, volume 97, number 10, May 2001, pages 2962-2971.

10. Sanz, M.A. Cord-Blood Transplantation in Patients with Leukemia—A Real Alternative for Adults: Editorial. New England Journal of Medicine, volume 351, number 22, November 24, 2004.

11. Rocha, V., et al. Transplants of Umbilical-Cord Blood or Bone Marrow from Unrelated Donors in Adults with Acute Leukemia. New England Journal of Medicine, volume 351, number 22, November 24, 2004, pages 2276-2285.

12. Laughlin, M.J., et al. Outcomes After Transplantation of Cord Blood or Bone Marrow from Unrelated Donors in Adults with Leukemia. New England Journal of Medicine, volume 351, number 22, November 24, 2004, pages 2265-2275.


January 2008