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Overview
"Umbilical cord blood transplant is an important
alternative stem cell source for both children and adults with
hematologic malignancies. Umbilical cord blood units are rapidly
available and have less stringent human leukocyte antigen (HLA)
matching requirements.
Mismatch at two antigens actually improves the risk of relapse
for umbilical cord blood transplant recipients with relatively
low risk of severe acute or chronic graft vs host disease.
However, umbilical cord blood transplant is associated with an
inferior neutrophil recovery rate when compared to other stem
cell sources.
It is for this reason that we have explored ‘double unit
umbilical cord blood transplants,’ not only as a platform for
evaluating the safety and effectiveness of new methods of ex
vivo expansion or methods of enhanced homing, but also as an
approach itself to remedy the problem of limited cell dose,
particularly for adults.
A
stem cell transplant* may sometimes be medically necessary
for patients with lymphomas.
With a stem cell transplant, the
stem cells** obtained from
bone marrow,
peripheral blood, or umbilical cord blood are given back to the
patient following high dose treatment, which can damage or ablate
(kill off) these vital cells. The engrafted stem cells
can then restore bone marrow
function** impaired or destroyed by the high dose conditioning
therapy.
A stem cell transplant is sometimes called a bone
marrow transplant.
*The terms stem cell transplant,
infusion,
rescue, engraftment, or support may be used
interchangeably and essentially have the same meaning.
** Stem cells are "immature cells
known as hematopoietic or blood-forming stem cells.
Hematopoietic stem cells divide to form more blood-forming stem
cells, or they mature into one of three types of blood cells:
white
blood cells, which fight
infection;
red
blood cells, which carry oxygen; and
platelets,
which help the blood to clot. Most hematopoietic stem cells are
found in the bone marrow, but some cells, called peripheral
blood stem cells (PBSCs), are found in the bloodstream. Blood in
the umbilical cord also contains hematopoietic stem cells. Cells
from any of these sources can be used in transplants" [in
order to restore bone marrow function.] -
cancer.gov
The different types of
stem cell transplants are named from the
origin of the stem cells:
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allogeneic -
stem cells harvested from donor
(following reduced for full intensity therapy)
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autologous - stem cells harvested from self
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syngeneic
- stem cells harvested from
identical twin |
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cord blood - stem cells from saved
cord blood, from self or donor |
Cord
blood is now being investigated as a source of stem cells for patients
receiving high dose treatment for lymphoma and other cancers.
Q&A:
How does a cord blood transplant compare with other types?
"Cord Blood Cord blood transplants are a "type" of allogeneic transplant. The
reason they are different is that the stem cells found in the cord blood are more immunologically naive than the stem cells from marrow.
As a result, they are more "forgiving" when it comes to inducing graft
versus host disease (GVHD). This is when the donor cells start attacking the host (or recipient) of the transplant as if it were an
infection.
GVHD is one of the more feared complications of allogeneic transplantation. The biggest problem is that "some" GVHD is helpful in
that it helps to control the leukemia. This "beneficial" part is termed graft versus leukemia (GVL) effect. You need some of the
GVL, and can tolerate some GVHD, but you do not want too much as it can be
lethal.
Cord blood, because it is less developed immunologically is thought to
cause less GVHD. We do not yet know if it the less GVHD results in less GVL and less effectiveness in
controlling the disease. "
~ Rick Furman, MD (Sept 2008)
Also see: How are umbilical cord stem cells obtained for
transplantation?
Cancer.gov
Resources:
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