Acute motor neuropathy with antibodies to GM1 ganglioside.

We describe a 52-year-old man who had an acute-onset purely motor neuropathy fulfilling the diagnostic criteria for the Guillain-Barré syndrome, in whom virtually complete spontaneous recovery occurred by 1 year, and in whom high titres of polyclonal serum antibody to GM1, GD1b, asialo-GM1 and lacto-N-tetraose were detected. The titre of IgM antibody to GM1 fell during the course of the disease with a concomitant rise in the IgG titre. This case adds to the widening spectrum of disease associated with anti-GM1 antibodies and provides further evidence for a relationship between anti-GM1 antibodies and motor system disease.