More MS news articles for November 2000

New Research in Multiple Sclerosis: Active HHV-6 Infections in Patients with Early Disease

11.14.2000 Press Release

The Institute for Viral Pathogenesis (IVP), a not-for-profit research organization, announces the results from a breakthrough new study published in the October issue of the journal Clinical Infectious Diseases. The study demonstrates that patients with multiple sclerosis (MS) were found to have a significantly greater incidence of an active virus infection called Human Herpesvirus Six (HHV-6) compared to controls.

An estimated third of a million Americans have multiple sclerosis, a chronic disease affecting the central nervous system. Nearly 200 cases of MS are diagnosed every week. In MS, an immune system reaction causes a breakdown in the fatty substance called myelin which surrounds and protects nerve fibers. The symptoms of MS run the gamut from slight blurring of vision to complete paralysis.

Dr. Konstance Knox, the lead investigator of the study states: "Loss of myelin (white matter) is the most common pathologic change seen in patients with HHV-6 associated central nervous system disease and loss of myelin is the landmark finding in the disease, multiple sclerosis". Dr. Joseph Brewer, an infectious disease specialist and one of the investigators states: " This new information demonstrating active HHV-6 infection in patients with multiple sclerosis is an important addition to our understanding of the role of this virus in chronic neurologic diseases".

In the study, sponsored by the National MS Society, cells actively infected with HHV-6 were found in central nervous system tissues from 8 (73%) of 11 patients with MS by means of immunohistochemical staining. Interestingly, 17 (90%) of 19 tissue sections showing destruction of myelin were positive for HHV-6 infected cells compared with only 3 (13%) of 23 tissue sections free of active disease (p<.0001).
 
In an effort to find out if HHV-6 infection in MS patients was systemic or restricted to the central nervous system, lymphoid tissue and blood samples were evaluated. Lymphoid tissue from 9 MS patients were evaluated and compared to lymphoid tissue from 7 healthy subjects. Active HHV-6 infections were found in 67% (6/9) of the patients with MS while none of the control subjects had active HHV-6 infection (p.<0.015). By use of a rapid culture assay, blood samples from 22 (54%) of 41 patients with MS were found to contain active HHV-6 infections, compared with 0 of 61 normal controls (p<.0001).

The study found the incidence of active HHV-6 infection is significantly increased in MS patients with disease durations of <12 years. Active HHV-6 infections were found in both relapsing remitting MS patients and progressive MS patients.

Active HHV-6 infections have been problematic to detect in the past. IVP scientists Drs. Konstance Knox and Donald Carrigan developed the detection methods used for HHV-6, which were pivotal to the findings of the study. Dr. Knox states: "The ability to identify active HHV-6 infections by relatively noninvasive means in patients with MS has important implications with respect to therapeutic interventions in these patients. The effectiveness of an antiviral drug on suppression of HHV-6 could be monitored by analysis of a simple blood sample". Dr. Brewer states: "It is intuitive that control of the active HHV-6 infection may alter the course of the disease state and prove to be an important addition to the treatment of diseases such as multiple sclerosis. Our group, as well as others, have been diligently looking at various treatment modalities to control the active infection which we hope will help with these chronic diseases".

In summary, most if not all patients with MS have active HHV-6 infections in their central nervous system tissues, lymphoid tissues, and peripheral blood. Such infections are not seen in normal controls. The finding that active HHV-6 infections can be identified by relatively noninvasive means (Rapid HHV-6 Culture on blood samples) has important implications with respect to therapeutic intervention in those patients. Controlling active HHV-6 infection could alter the course of the disease and give us important insights into the role of this virus in initiating and perpetuating the disease process.

About IVP The Institute for Viral Pathogenesis (IVP) located in Milwaukee, Wisconsin, was organized and is operated exclusively for the charitable and scientific purpose of identifying new viral pathogens of humans and exploring the roles of newly identified viruses as emerging pathogens. IVP researchers Dr. Konstance Knox and Dr. Donald Carrigan receive their support in the form of research grants from private foundations, universities, individuals and corporations with an interest in contributing to the medical and scientific understanding of viral diseases. Institute for Viral Pathogenesis 10437 Innovation Drive, Suite 417 Milwaukee, Wisconsin 53226 (414) 774-8305

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Joseph Brewer, MD, Division of Infectious Diseases, St. Luke's Medical Center, Kansas City, Missouri.

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