Wednesday June 13 5:01 PM ET
"Umbilical Cord Might Help Leukemia"
Umbilical Cord Might Help Leukemia
By LINDA A. JOHNSON, Associated Press Writer
Blood from umbilical cords can build new immune systems for
adults with leukemia, offering a potentially lifesaving treatment
for the many patients who cannot find suitable bone marrow donors.
Currently, an estimated 4,000 to 6,000 Americans die each year
while awaiting a bone marrow match.
Until now, stem cells drawn from umbilical cord blood have been
reserved mostly for treating children. Because an umbilical cord
contains only one-tenth as many stem cells as a marrow donation,
experts believed there was too little tissue to reconstitute the
immune defenses of an adult.
However, new research shows that because the umbilical cord
cells proliferate so rapidly, they can indeed be used to treat
In the first U.S. study of cord blood transplants in adults,
researchers at University Hospitals of Cleveland and other sites
gave 68 adults cord blood transplants from unrelated donors.
While infections, bleeding and other complications killed many
of the patients within months, nearly one-third survived long term,
about the same as with bone marrow transplants.
"This field will explode" and may even replace bone marrow and
other sources of stem cells, said Dr. Andrew L. Pecora, director of
the blood and marrow stem cell center at Hackensack University
Medical Center in New Jersey. "Cord blood transplantation holds
the promise of making it so everyone has a donor."
The research is reported in Thursday's New England Journal of
Medicine (news - web sites).
Stem cells, collected from bone marrow or circulating blood in
adults or from cord blood, are immature cells that can develop into
any type of blood cell: oxygen-carrying red blood cells, clotting
platelets or infection-fighting white blood cells.
In patients with leukemia and other blood disorders, doctors
destroy the cancer and the immune system with chemotherapy or
radiation, then replace the patient's immune- and blood-forming
system with a transplanted one.
Cord blood stem cells are collected by hospitals before
placentas are discarded and so do not involve the controversy over
use of stem cells from fetuses. Cord blood cells, stored frozen at
public stem cell banks, offer other key advantages.
They are immunologically "naive," unlike cells from adults,
and are thus far less likely to trigger a common, life-threatening
complication called graft-versus-host disease, in which the
transplanted immune system attacks the patient's tissue. In this
study, only 18 percent of patients developed the complication,
about the rate in patients getting marrow from a matched sibling.
That gives doctors far more leeway in finding a matching
stem-cell donor. Currently, only about 60 percent of white
Americans now find a suitable donor, and the rates for minorities
range from just 20 percent to 50 percent.
In addition, Dr. Mary J. Laughlin, director of the transplant
program at University Hospitals of Cleveland, noted that a cord
blood stem cell match can be located and prepared within weeks,
rather than the months it takes to arrange a bone marrow
And cells from newborns are unlikely to contain a virus
dangerous to transplant patients that lurks harmlessly in most
Laughlin expects that within five years, stem cells from cord
blood will be used for repairing damaged blood vessels in heart and
stroke patients, repairing brain tissue in Parkinson's disease (news - web sites)
patients and, in diabetics, replacing pancreas cells that are not
producing enough insulin.
Meanwhile, because cord blood cell recipients fare better the
more cells they receive, Pecora and other researchers are
developing ways to make stem cells from cord blood multiply in the
lab so there are more cells to transplant.
Liana Harvath, director of the blood resources program at the
National Heart, Lung and Blood Institute, said researchers also
must find a way to cut the time it takes for cord blood stem cells
to build new immune- and blood-forming systems.
In an editorial, Dr. Eliane Gluckman of Hopital Saint-Louis in
Paris called the results remarkable but recommended that doctors
still search both bone marrow and cord-blood registries to find the
best available match.
On the Net: http://www.nejm.com
National Marrow Donor Program: http://www.marrow.org
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