Is Cord Blood Transplantation the Right Choice for You?

If you have leukemia or a serious blood disease, your doctor may want to treat you with a bone marrow or cord blood transplant. Both adult bone marrow and the blood taken from a baby's umbilical cord contain stem cells, which are a special type of cell that has the potential to grow into many different types of cells. Adult stem cells can grow into a variety of different types of blood cells, as well as continue to produce more adult stem cells. Stem cells from umbilical cord blood, on the other hand, are a little more flexible, as they’re less mature.

First used in 1988, an umbilical cord blood transplant has some distinct advantages and disadvantages over an adult bone marrow transplant. Your doctor will carefully weigh all of these factors when making decisions about your care. However, it’s important to know that umbilical cord blood transplants are less common and many doctors are still learning about them.

One consideration is volume. The volume of cells available needs to match the volume of cells needed by the patient. Babies and adults obviously have very different blood volumes. Umbilical cord blood transplants are more commonly used for children than adults for this reason. However, for adults, there’s always the possibility of receiving two umbilical cord blood units instead of one. In addition, researchers are also looking for ways to increase the number of stem cells available by growing them under laboratory conditions.

If there’s a possibility you may need an additional transplant, then umbilical cord blood – because of its limited volume – may not be a good choice. With an adult bone marrow transplant, there’s the possibility of getting a second donation, while umbilical cord blood from a single individual is a finite resource.

Another consideration is the closeness of the match. To prevent rejection and other negative outcomes, the donor transplant must match the recipient's blood type as closely as possible. Rather than just the general classification of O, A or B blood types as we commonly think of them, there are a number of additional factors that must match as well. In fact, it could be that the best match for a particular patient is cord blood, rather than adult bone marrow. Not only may a unit of umbilical cord blood match more closely, it may also be more readily available because it’s already in storage. The average time to receive a unit of umbilical cord blood is about two weeks, whereas locating the appropriate adult donor and securing the adult bone marrow unit can take two months or more.

However, anytime there’s a transplant, there’s the possibility of incompatibility. We commonly think of the host or recipient's body attacking and rejecting the transplant, but the process can also happen in reverse. When the transplanted material attacks the host, the condition is known as graft versus host disease. This occurs less often when umbilical cord blood is used. On the other hand, it can also take longer for an umbilical cord blood transplant to “take” and begin growing new blood cells. This longer wait can leave the host patient vulnerable to infection for a longer period of time.

The use of umbilical cord blood for transplantation is a new practice and there is, consequently, less information about its success in the long term. With additional study, however, this new tool may prove to be a formidable one in our arsenal against disease.