Stem Cell Treatment for Leukemia Improved
Transplant Technique Speeds Immune System Recovery
Jan. 19, 2010 -- Leukemia patients who receive stem cell transplants from
the umbilical cord blood of newborns are usually vulnerable to life-threatening
infections for at least a month as their immune systems recover.
Now researchers from Seattle’s Fred Hutchinson Cancer Center may have found
a way to dramatically shorten this recovery period and reduce infection-related
In a small, early study, the researchers were able to successfully
manipulate umbilical cord-derived stem cells to speed the production of
infection-fighting white blood cells.
It took about two weeks for the transplanted cells to start making white
blood cells on their own -- a process known as engraftment -- compared to a
month when patients got the non-manipulated cord blood.
The research appears in the Jan. 17 issue of the journal Nature
“If we really can make stem cell sources better, this may mean we would have
donors for pretty much everyone who needs a transplant,” study researcher
Colleen Delaney, MD, tells WebMD.
Many Patients Can’t Find Matches
Stem cell transplants are performed in some patients with leukemia and other
blood cancers to help the body make new blood cells after its own blood cells
have been destroyed by disease or cancer treatments.
But cord blood contains only about one-tenth of the stem cells found in bone
marrow, and this is why cord blood transplants usually take so much longer to
The advantage of cord blood transplants is that they do not need to be as
perfectly matched to the patient as bone marrow transplants.
Close to one in three patients -- and as many as 95% of non-white patients
-- who could benefit from a stem cell transplant never find a suitable
Researchers have long sought ways to increase the number of stem cells in
cord blood in an effort to speed the production of infection-fighting white
In the new research, the Fred Hutchinson researchers manipulated a system
known as the Notch signaling pathway, which is involved in embryonic
By engineering a protein that activated the pathway, the researchers were
able to expand the number of stem cells in a single unit of cord blood about
164-fold -- from 200,000 stem cells per kilogram of body weight to 6
In a phase I study, 10 leukemia patients were treated with one unit of
non-manipulated cord blood and one unit manipulated in the lab.
It took 14 days for the manipulated stem cells to engraft versus four weeks
for the non-manipulated cells.
“We have shown that we can decrease the time to engraftment,” Delaney says.
“Now we have to show a clinical benefit to the patient.”
Larger, Longer Cord Blood Study Planned
The researchers will attempt to do this in a much larger clinical trial.