Researchers Expand Natural Killer Cells In Cord Blood To Fight
Leukemia
M. D. Anderson News Release 05/16/08
Researchers from The University of Texas M. D. Anderson Cancer Center
have found a therapy that effectively kills human leukemia cells in
mice using natural killer (NK) cells from umbilical cord blood.
Patrick Zweidler-McKay, M.D., Ph.D., assistant professor of
pediatrics from the Children's Cancer Hospital at M. D. Anderson, has
shown an effective method for expanding the number of NK cells from a
single cord blood unit while retaining the cells' anti-leukemia
effects, as presented at the American Society of Pediatric
Hematology/Oncology annual conference on May 16.
Previous efforts to expand cord blood have resulted in ineffective NK
cells. However, Zweidler-McKay and co-senior investigator Elizabeth
Shpall, M.D., professor in M. D. Anderson's Department of Stem Cell
Transplantation and Cellular Therapy, have found a novel process to
increase NK cells in cord blood more than 30-fold, generating more
than 150 million NK cells from one cord blood unit while maintaining
their activation to find and kill acute leukemia cells.
When given to mice with aggressive human leukemias, these NK cells
reduced the circulating human acute lymphocytic leukemia (ALL) and
acute myelogenous leukemia (AML) cells by 60 to 85 percent.
"Cord blood is a promising source of natural killer cells because the
NK cells have enhanced sensitivity to stimulation, decreased
potential to cause graft-versus-
cord banks throughout the country and world," says Zweidler-McKay.
NK Cells Spare Normal Cells While Attacking ALL and AML
Graft-versus-
receiving stem cell transplants, which results when the T cells in
the transplanted blood react against the patient's own cells. This
disease can become fatal if it's unable to be controlled. NK cells
operate differently from T cells, leaving normal cells alone while
targeting and killing the cancerous cells.
Historical transplants used a matched donor's peripheral blood or
bone marrow to transplant to a patient. However, in 1988, researchers
found cord blood to be another source for stem cell transplantation.
These immature stem cells were easier to match to patients,
especially those from non-Caucasian ethnicities, and could be stored
for use as needed.
Zweidler-McKay'
blood. As the cord blood is expanded to multiply in number, the NK
cells are given a cytokine, interleukin-
which keep the NK cells active throughout the three week expansion.
Once the process is complete, the NK cells can be transplanted to
patients without prior chemotherapy. Zweidler-McKay also predicts
this type of transplant could be used for adults who have already had
a transplant or for those adult and pediatric patients who aren't
candidates for other stem cell transplants due to blood counts or
illness.
"These NK cells demonstrate significant cytotoxic activity against
human AML and ALL cell lines and patient leukemia blasts. Most
importantly, mouse models of human AML and ALL were sensitive to NK
cell infusions," says Zweidler-McKay. "These results support the
evaluation of cord blood-derived NK cells as a potential immuno-
therapeutic approach in acute leukemias."
Lead investigator on the study is Dongxia Xing, Ph.D., and Zweidler-
McKay and Shpall are senior investigators, all from M. D. Anderson.
05/16/08
http://www.mdanders
id=FDA6EF7B-
c468-11d4-80fb00508
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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