[A case of Guillain-Barré syndrome associated with anti-GM2 antibody due to cytomegalovirus infection--special reference to the effect of ganciclovir].

We report a case of Guillain-Barré syndrome (GBS) associated with anti-GM2 antibody caused by cytomegalovirus (CMV) infection. A 27-year-old man was admitted to our hospital because of muscle weakness in all his extremities. He had no background of immunological abnormalities. Within 5 days, generalized muscular weakness had progressed so rapidly that he suffered respiratory dysfunction and dysphagia. Throughout the entire clinical course, enzyme immunoassay (serum) and enzyme-linked immunosorbent assay (CSF) for CMV were carried out serially. Only antibodies against CMV were elevated during the clinical course in the serum and CSF. These findings supported the idea that he had developed GBS due to isolated CMV infection. We examined the reactivity of GBS sera with crude ganglioside fraction, and only anti-GM2 antibody was recognized on a high-performance thin-layer chromatogram plate in this case. Although the anti-GM2 antibody was decreased transiently by plasmapheresis, the clinical symptoms progressed. The symptoms advanced very rapidly during high-dose gammaglobulin therapy associated with reelevation of the anti-GM2 antibody. Following ganciclovir administration, however, the symptoms became diminished within 7 days and the anti-GM2 antibody fell dramatically. We speculate that the reason for the observed effectiveness of ganciclovir was direct suppression of activation of CMV, followed by the inhibition of the production of demyelinating antibodies including the anti-GM2 antibody.