By 2006, about 50 children had received cord blood transplants at Seattle Cancer Care Alliance. As this source of stem cells expands, the transplant donor pool expands as well, making stem cell transplants available to a greater number of patients. This can be especially important for ethnic minorities and those who have mixed ethnicity or unusual tissue types—in all these cases, it’s more difficult to find a suitably matched donor.
Stem cells for a hematopoietic cell transplant can come from three sources: bone marrow, peripheral blood (the blood that circulates around your body) or the blood that remains in the umbilical cord when a mother and newborn are separated. Most cord blood is discarded. But some is collected in banks so that people who need stem cell transplants can use it.
The stem cells from cord blood are more versatile than those from bone marrow or peripheral blood, simply because the infant donor’s immune system is immature. The stem cells are relatively “uneducated” compared to cells from an older child or an adult. So there’s less likelihood of an adverse interaction between the transplanted cells and the recipient’s cells. This means that in order to be useful, stem cells from cord blood do not have to match the recipient’s tissue as closely as bone marrow or peripheral blood stem cells do.
Other than the source of the stem cells, a cord blood transplant is very similar to a bone marrow or peripheral blood stem cell transplant. The main difference is that it sometimes takes longer for the transplanted cells to engraft—to establish themselves in the recipient’s body and begin producing blood cells. Longer time to engraftment means more time without adequate numbers of the white blood cells that guard against infection.
Source: Seattle Cancer Care Alliance
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