Ancient Retrovirus May Contribute to Chronic Fatigue Syndrome, Multiple Sclerosis and Autoimmunity

Mon Jun 23, 2008 10:01am EDT

* Reuters is not responsible for the content in this press release.

Brigitte Huber, PhD, of the Tufts University School of Medicine,
presented evidence at a medical conference that suggested that a
reactivated ancient retrovirus embedded in the human genome may be active
in chronic fatigue syndrome (CFS) and multiple sclerosis (MS) patients.
Danish scientists at the same conference suggested that the activation of
this retrovirus, dormant in healthy individuals, could be the reason why
autoimmune conditions worsen with viral infections.

    Chronic Fatigue Syndrome and Multiple Sclerosis Patients at Increased Risk
From the Effects of HERV-K18 Activation

    "Patients with profoundly fatiguing diseases such as MS and CFS may be
particularly susceptible to HERV-K18 activation," said Dr. Huber. The
announcement was made at the International Symposium on Viruses in CFS and
Post-Viral Fatigue, a satellite conference of the 6th International
Conference on HHV-6 & 7. Using an SNP-based genotyping method, Dr. Huber
found that both MS and CFS patients (whose illness had been triggered by
infectious mononucleosis) were at a higher relative risk for containing
HERV-K18 variants known to induce superantigen activity. Superantigens are
proteins that are able to induce a strong undifferentiated T-cell response
believed to deplete the immune system over time.

    Viral activity and/or immune activation has been shown to trigger HERV-K18
activity. Both Epstein-Barr virus infection (infectious mononucleosis) and
interferon-alpha administration are associated with HERV-K18 activity.
"HHV-6 activates HERV-K18 as well," said Danish investigator Per
Hollsberg, MD and professor from the University of Aarhus In Denmark. His
PhD student Vanda Lauridsen Turcanova presented this data at the same
conference. "Furthermore, this retrovirus activation may have important
consequences for autoimmunity," he added.

    HERV-K18 activation may be the endpoint of an HHV6/EBV interferon pathway
operating in both MS and CFS. HHV-6 is being investigated as a co-factor
in both diseases. Other retroviruses, HERV-H and HERV-W, have been
implicated in MS by other researchers. Over 75% of MS patients meet the
criteria for CFS. Fatigue is often the most disabling symptom for MS
patients. The two diseases also share characteristics such as grey matter
atrophy, impaired cerebral glucose metabolism, autonomic nervous system
activity and altered patterns of brain activity.

    Dr. Huber's study suggests that endogenous retroviral activation in CFS
and MS could produce some of the symptoms associated with both diseases.
She has received a National Institutes of Health (NIH) grant to study
these issues. Per Hollsberg has done extensive research on the role of
EBV and HHV-6 in multiple sclerosis.

    The HHV-6 Foundation

    The HHV-6 Foundation encourages scientific exchanges and provides grants
to researchers seeking to increase our understanding of HHV-6 infection
in a wide array of central nervous system disorders. Daram Ablashi, the
co-discoverer of the HHV-6 virus, is the Foundation's Scientific Director.


Kristin Loomis
Executive Director
HHV-6 Foundation
Santa Barbara, CA

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