Umbilical cord blood is playing an important and growing role in the treatment of leukemia, lymphoma and other life-threatening blood diseases. If you have been told a bone marrow transplant is a possible treatment for your disease, a cord blood transplant may be an option.
Cord blood basics
Umbilical cord blood is one of three sources for the blood-forming cells used in transplants. The other two sources are bone marrow and peripheral (circulating) blood. The first cord blood transplant was done in 1988. Cord blood plays an important role in transplant today. Doctors are still learning about the ways cord blood transplants are similar to and different from marrow or peripheral blood transplants.
Umbilical cord blood is collected from the umbilical cord and placenta after a baby is born. This blood is rich in blood-forming cells. The donated cord blood is tested, frozen and stored at a cord blood bank for future use. The stored cord blood is called a cord blood unit. To learn more about how cord blood is collected, see Umbilical Cord Blood Donation.
The Be The Match Registry®, operated by the National Marrow Donor Program® (NMDP), includes nearly 185,000 cord blood units. Doctors search the registry of adult marrow or peripheral blood cell donors and cord blood units to find a suitable HLA match for their patients who need a transplant. If selected, the matching cord blood is transplanted to a patient. The transplant process is the same as for marrow and peripheral blood cell transplants.
Patients treated with cord blood transplants
The use of cord blood transplants has grown for both children and adults. Cord blood is used more often in children because a cord blood unit has a limited amount of blood-forming cells. Smaller patients need fewer cells and larger patients need more cells. Because some cord blood units may not have enough cells for larger patients, they are sometimes transplanted using two or more cord blood units combined.
Another method being studied is to grow the number of cells in a cord blood unit in a laboratory before giving it to the patient.
Reasons doctors may choose cord blood
When your doctor contacts the NMDP to search the Be The Match Registry, he or she will choose the best cell source for you. That may be marrow or peripheral blood from an adult donor or it may be a cord blood unit. A doctor might choose cord blood because of some of the ways it differs from marrow or peripheral blood.
More tolerant matching
A close match between the patient and the donor or cord blood unit can improve a patient's outcome after transplant. Even though a closely matched cord blood unit is preferred, clinical studies suggest the match may not have to be as close as is needed for marrow or peripheral blood transplants. If you have an uncommon tissue type, your doctor may not find a closely matched adult donor for you. However, a cord blood unit may be an option.
More quickly available
Cord blood units are stored and ready to use. A cord blood unit can be selected and delivered to the transplant center in less than two weeks whereas it can take two months or more to find an unrelated marrow or peripheral blood donor. Your doctor may choose cord blood if you need a transplant quickly.
Less graft-versus-host disease
Graft-versus-host disease (GVHD) is a common complication after an allogeneic transplant (which uses cells from a family member, unrelated donor or cord blood unit). GVHD can range from mild to life-threatening. Studies have found that after a cord blood transplant, fewer patients get GVHD than after marrow or peripheral blood transplants. Patients in the studies who did get GVHD after a cord blood transplant tended to get less severe cases.
Reasons doctors may not choose cord blood
There are also reasons a doctor may choose not to use cord blood for a transplant, including:
Number of Cells
There may not be enough blood-forming cells in a cord blood unit for the size of the patient.
Time to Engraft
It usually takes longer for cord blood cells to engraft (begin to grow in the patient and create new blood cells and an immune system). Until the cells engraft, the patient is at a high risk for infection.
Patients cannot get backup cells from the same cord blood unit. If a patient's transplanted marrow or peripheral blood cells do not engraft or the patient relapses, the patient may be able to get a second donation from the same adult donor. After a cord blood transplant, this option is not available. However, doctors may be able to use a different cord blood unit or a backup adult donor instead.
Cord blood is a newer treatment approach for transplant. Doctors do not have as much information about patients' long-term results after cord blood transplants as they do for marrow transplants.
Cord blood transplants also have all the same risks as marrow and peripheral blood transplants. The risk of infection may be higher after a cord blood transplant because of the longer time to engraft. The risk of GVHD may be lower, but the risk is still there.
If you have questions about whether a cord blood transplant is right for you, talk with your transplant doctor. Every patient's situation is different. Your transplant doctor knows your situation and can help you make choices about your treatment.