Date: July 4, 2011
Author: Nina Bai
URL: http://www.scientificamerican.com/article.cfm?id=3Ddonor-fatigue
Donor Fatigue
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The Red Cross has banned chronic fatigue syndrome sufferers
from giving blood. But does a virus really cause the
disease?
Scientists may still be debating the role of viruses in
chronic fatigue syndrome, but blood banks aren't taking
any chances. Last summer the AABB, a nonprofit that
represents blood-collecting organizations, advised people
with the disorder, marked by severe fatigue and aches
lasting six months or more, to self-defer from blood
donation. Last December the American Red Cross went
further, banning people who revealed during a predonation
interview that they had the syndrome from ever giving
blood at its centers.
The cause for this abundance of caution is XMRV
(xenotropic murine leukemia virus?related virus), a
retro=ADvirus that has been associated with chronic fatigue
syndrome. In a highly publicized 2009 study published in
Science, XMRV was found in 67 percent of patients and
3.7 percent of healthy controls. But subsequent studies
failed to find the virus in people with or without the
syndrome, suggesting to some that XMRV may be a
laboratory contaminant that skewed the initial trial.
How worried should one be about XMRV in the blood
supply? Not very. There has been no evidence of anyone
contracting chronic fatigue syndrome from a blood
transfusion, so the risk is hypothetical. And more
stringent measures, such as screening potential donors
for the syndrome via questionnaire, would take attention
away from diseases such as HIV and hepatitis B that are
unequivocally blood-borne, says Harvey Klein, chair of
the AABB task force examining this issue.
Still, experts are weighing whether or not to test
donated blood. The first step in that process is
agreeing on a standard method for detecting the virus
in the blood. A team at the National Heart, Lung, and
Blood Institute is comparing the different nucleic acid
tests and blood-sample preparation techniques used by
various labs?including the Centers for Disease Control
and the Food and Drug Administration - to find the best
one.
If the test that comes out on top confirms the results
of the 2009 study, that is, if it consistently detects
XMRV in blood samples from chronic fatigue syndrome
patients and does not detect it in negative controls,
'we will have identified sensitive and specific methods
to detect XMRV in blood samples,' says Simone Glynn,
who chairs the NHLBI working group overseeing the study.
The next step would be to use that test to check for the
presence of XMRV in large numbers of blood donor
samples. If the virus is prevalent, the team would
examine frozen blood samples and check for evidence of
transfusion transmission. 'Conversely, if we do not find
evidence of XMRV in the blood samples from patients with
chronic fatigue syndrome who were previously found to be
positive, we would conclude that these viruses do not
appear to be present in blood,' Glynn says.
For now, excluding people with the syndrome from blood
donation is prudent, says Ian Lipkin, director of the
Center for Infection and Immunity at the Columbia
University Mailman School of Public Health, who is
heading the National Institutes of Health?funded
investigation into the connection between chronic
fatigue syndrome and XMRV. 'My sense is that the number
of people with the syndrome likely to be sufficiently
fit to make blood donations is so few that the Red Cross
and AABB have decided for a variety of reasons,
scientific and otherwise that it's just not worth the
risk.'
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(c) 2011 Nature America, Inc.
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