Stem cell transplants are designed to replace the patient’s unhealthy cells with healthy ones. The most common sources of these healthy cells are the umbilical cord blood and bone marrow.
Cord blood is blood that is collected from an infant’s umbilical cord after delivery, so that it may be tested, frozen, and subsequently stored in a cord blood bank for future use.
A bone marrow transplant, on the other hand, involves the use of bone marrow that is transplanted from a donor into the recipient in order to cultivate new stem cells.
The marrow itself is a spongy tissue located inside the bones. Most commonly, marrow is extracted from either the breastbone, skull, hips, ribs or spine, as these contain stem cells which produce the following types of blood cells: white blood cells (leukocytes), which fight against infection; red blood cells (erythrocytes), which carry oxygen in order to eliminate waste from the organs and tissue; and platelets, which are responsible for making the blood clot.
When cord blood stem cells are preferred for transplant than bone marrow stem cells:
There are several criteria used to evaluate whether cord blood stem cells should be used for transplant instead of bone marrow stem cells to treat a patient. A transplant physician will keep the following factors in mind:
- Graft Versus Host Disease (GVHD) – Graft Versus Host Disease (GVHD) is a potentially serious complication for any organ transplant. In fact, it is estimated to be fatal in up to 40% of patients. However, because cord blood stem cells are more primitive than bone marrow stem cells, there is a lower chance that these cells will attack the recipient’s body, resulting in a lower evidence of GVHD.
- HLA Matching – Human Leukocyte Antigen (HLA) is a marker your immune system uses to recognize foreign cells. HLA tissue types are inherited, which is why it is recommended that a recipient’s bone marrow donor be a family member (ideally a brother or sister). This is a problem because 70% of donors do not have a suitable donor in their family. However, because cord blood stem cells are considered to be “younger” (and therefore more adaptable), there is generally less need to find an exact HLA match.
- Rich Source of Stem Cells – Stem cells are found in greater proportions in umbilical cord blood. In fact, some experts say it contains nearly 10 times the amount of stem cells found in the bone marrow.
- Regenerative Source – It is believed that stem cells found in cord blood have greater regenerative properties since they are younger than bone marrow.
- Availability – Stem cell transplants are in high demand, with over 30,000 individuals in line for the procedure each year. The problem is that waiting for a suitable donor can often inhibit an individual from having the procedure. In fact, for this very season, 70% of these individuals cannot find a matching donor. Unfortunately, for some individuals, such as those with more severe types of cancer, this lack of treatment can be fatal. Cord blood banking, however, helps to alleviate this issue, as their storage facilities make cord blood readily available for those in need.
- Pain – From a donor’s perspective, a cord blood transplant presents a much less invasive procedure, as the collection of cord blood stem cells happens directly after birth from the umbilical cord. Bone marrow transplants, on the other hand, are invasive procedures, requiring a general anesthesia so that bone marrow stem cells can be removed from the rear of the pelvic bone through a series of injections.
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