A treatable multifocal motor neuropathy with antibodies to GM1 ganglioside

TLDR

This study describes two patients with a treatable, immune‑mediated motor polyneuropathy linked to antibodies against neural antigens. The patients showed progressive asymmetric weakness with multifocal conduction blocks, high GM1 antibody titers, and improved strength after cyclophosphamide following unsuccessful prednisone and plasmapheresis trials.

Abstract

We report 2 patients with a treatable, immune-mediated motor polyneuropathy associated with antibodies to defined neural antigens. In these patients asymmetrical weakness developed in one arm and progressed over 2 to 3 years to involve the other arm, legs, and trunk. Both patients were initially diagnosed as having lower motor neuron forms of amyotrophic lateral sclerosis. However, repeated electrophysiological testing eventually showed multifocal conduction blocks in motor but not sensory fibers compatible with patchy selective demyelination. Serum testing by thin-layer chromatography and enzyme-linked immunosorbent assay revealed that both patients had high titers of antibody directed against GM1 and other gangliosides. Initial therapeutic trials of prednisone (100 mg daily for 4 to 6 months) and plasmapheresis were unsuccessful. Treatment with cyclophosphamide, however, was followed by marked improvement in strength in both patients.