Stem cells from umbilical cord blood are hematopoetic
stem cells (like adult bone marrow stem cells), meaning that
they make blood cells. Receiving a cord blood transplant is similar
to receiving a bone marrow transplant. The cord blood is removed
from the umbilical cord and the placenta soon after a baby is born.
Technicians or Physicians collect 3-5 ounces of blood from the cord
and placenta which contains about a teaspoon of stem cells.
Potential advantages of cord blood:
- The cells are somewhat more versatile than bone marrow cells,
meaning that cord blood transplants have the potential to successfully
treat a wider range of blood diseases.
- The HLA profile of cord blood, meaning how similar it is to the
recipient's own cells, does not need to match the recipient as closely
as does bone marrow. There is less chance of rejection of the transplant.
- There is a ready supply of cord blood, and collection of it does
no harm to mother or baby.
Disadvantages of cord blood:
- Finite source of cord blood stem cells. This means there often
aren't enough cells in one collection to treat an adult.
- Once a cord blood is transplanted, there are no more cells readily
available from that source.
- The cord blood stem cells take longer to graft into the patient
than do bone marrow transplants.
Another disadvantage of cord blood is that there is no centralized
(nationwide) system for collecting and storing of cord blood that is
donated. There are, however, private companies that will, for a fee,
store a baby's cord blood for their own possible use later in life.
Right now only a few hospitals collect donated cord blood and sometimes
it is only done for births that happen during particular hours of the
day. Also, there is some controversy over what organization should
oversee collection and storage of donated cord blood.
Will cord blood ever be more useful?
Researchers at the University of Minnesota and elsewhere are trying
to grow cord blood stem cells into other types of cells for new treatments.
They are also working to increase transplant success for larger
children and adults by multiplying the cells in the lab or by giving
transplants from more than one donor.