HHV-6 infection in multiple sclerosis. A clinical and laboratory analysis

Background and purpose: To elucidate the role of human herpesvirus-6 (HHV-6) in the development of multiple sclerosis (MS). Patients and methods: Nine patients with MS and with acute or chronic HHV-6 infection were evaluated. Results: Intrathecal antibody production to HHV-6 and oligoclonal IgG bands in the cerebrospinal fluid (CSF) was observed in two patients with a clinically definite MS and chronic HHV-6 infection (based on the presence of HHV-6 specific antibodies in the CSF). A temporal association between the symptoms of clinically possible MS and acute primary HHV-6A infection (based on avidity of HHV-6 specific antibodies) was observed in two patients. Conclusions: Human herpesvirus-6 infection may be an associated agent in some MS cases. Viral studies are needed to identify a possible viral etiology and give specific therapy.