Fulminant central nervous system demyelination associated with interferon-α therapy and hepatitis C virus infection

Hepatitis C virus (HCV) infection is common in the general population and may coincide with disease in the central and peripheral nervous system. Interferon-alpha (IFN-alpha) is used as treatment for HCV infection. The therapeutic benefit is assumed to result from activation of natural killer cells and CD8+ T cells. Despite its beneficial effects, it has been associated with a number of autoimmune disorders, such as chronic inflammatory demyelinating polyneuropathy and multiple sclerosis. Several clinical reports including magnetic resonance imaging exist, but neuropathological confirmation of MS associated with IFN-a therapy and HCV infection is lacking. We report a case of a female patient with chronic HCV infection who developed 'acute MS'-like demyelinating disease after IFN-a. administration, with extensive lesions throughout brain and thoracic spinal cord. The patient died after a disease duration of 6 months. Brain autopsy revealed Balo-like demyelinating plaques with positive HCV sequences within florid lesions. The development of fulminant demyelinating disease after administration of IFN-alpha suggests that autoimmune mechanisms such as T cell mediated tissue damage might be initiated or aggravated by IFN-alpha therapy. Additionally, the presence of HCV RNA within the demyelinated lesion indicates a possible role in triggering or propagating disease.