Scientists have
discovered a potential retroviral link to chronic fatigue syndrome, known as CFS
or ME, a debilitating disease that affects
millions of people in the United States. Researchers from the Whittemore
Peterson Institute (WPI), located at the University of
Nevada, Reno, the National Cancer Institute (NCI), part of the National
Institutes of Health, and the Cleveland Clinic, report this
finding online Oct. 8, 2009, issue of Science.
"We now have evidence that a retrovirus named XMRV is frequently present in the
blood of patients with CFS. This discovery could be a
major step in the discovery of vital treatment options for millions of
patients," said Judy Mikovits, Ph.D., director of research for WPI
and leader of the team that discovered this association. Researchers cautioned
however, that this finding shows there is an association
between XMRV and CFS but does not prove that XMRV causes CFS.
The scientists provide a new hypothesis for a retrovirus link with CFS. The
virus, XMRV, was first identified by Robert H. Silverman,
Ph.D., professor in the Department of Cancer Biology at the Cleveland Clinic
Lerner Research Institute, in men who had a specific immune
system defect that reduced their ability to fight viral infections.
"The discovery of XMRV in two major diseases, prostate cancer and now chronic
fatigue syndrome, is very exciting. If cause-and-effect is
established, there would be a new opportunity for prevention and treatment of
these diseases," said Silverman, a co-author on the CFS paper.
Commonality of an immune system defect in patients with CFS and prostate cancer
led researchers to look for the virus in their blood
samples. In this study, WPI scientists identified XMRV in the blood of 68 of 101
(67 percent) CFS patients. In contrast, they found that
eight of 218 healthy people (3.7 percent) contained XMRV DNA. The research team
not only found that blood cells contained XMRV but also
expressed XMRV proteins at high levels and produced infectious viral particles.
A clinically validated test to detect XMRV antibodies in
patients' plasma is currently under development.
These results were also supported by the observation of retrovirus particles in
patient samples when examined using transmission
electron microscopy. The data demonstrate the first direct isolation of
infectious XMRV from humans.
"These compelling
data allow the development of a hypothesis concerning a cause of this complex
and misunderstood disease, since
retroviruses are a known cause of neurodegenerative diseases and cancer in man,"
said Francis Ruscetti, Ph.D., Laboratory of
Experimental Immunology, NCI.
Retroviruses like XMRV have also been shown to activate a number of other latent
viruses. This could explain why so many different
viruses, such as Epstein-Barr virus, which was causally linked to Burkitt's and
other lymphomas in the 1970s, have been associated with
CFS. It is important to note that retroviruses, like XMRV, are not airborne.
"The scientific evidence that a retrovirus is implicated in CFS opens a new
world of possibilities for so many people," said Annette
Whittemore, founder and president of WPI and mother of a CFS patient.
"Scientists can now begin the important work of translating
this discovery into medical care for individuals with XMRV related diseases."
Dan Peterson, M.D., medical director of WPI added, "Patients with CFS deal with
a myriad of health issues as their quality of life
declines. I'm excited about the possibility of providing patients, who are
positive for XMRV, a definitive diagnosis, and hopefully very
soon, a range of effective treatments options."
The Whittemore Peterson Institute for Neuro Immune Disease exists to bring
discovery, knowledge, and effective treatments to patients with
illnesses that are caused by acquired dysregulation of both the immune system
and the nervous system, often resulting in lifelong
disease and disability.
www.wpinstitute.org.
From U.S. Department of Health and Human Services
NATIONAL INSTITUTES OF HEALTH NIH News
National Cancer Institute (NCI) <http://www.nci.nih.gov/>
Last Updated:
07/11/2009
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