Background: GM1 and GalNAc-GD1a are located on the axolemma of the motor nerves and are believed to be the antigens associated with pure motor Guillain-Barré syndrome (GBS). Furthermore, GM1 and GalNAc-GD1a may exist nearby and colocalize on the axolemma. Ganglioside complex (GSC) antigens associated with GM1 or GalNAc-GD1a can be target antigens in pure motor GBS. We investigated GBS sera for antibodies to a GSC consisting of GM1 and GalNAc-GD1a (GM1/GalNAc-GD1a) and analyzed the clinical and electrophysiologic findings of patients with antibodies to GM1/GalNAc-GD1a.
Methods: Sera from 224 patients with GBS were surveyed for antibodies to GSCs consisting of two of nine gangliosides (GM1, GM2, GM3, GD1a, GD3, GT1a, GT1b, GQ1b, and GalNAc-GD1a). We analyzed the clinical and electrophysiologic features of patients with IgG antibodies to the GM1/GalNAc-GD1a complex.
Results: Ten patients with GBS had IgG antibodies to the GM1/GalNAc-GD1a complex. The clinical findings of the 10 patients with GBS were characterized by preserved sensory system and infrequent cranial nerve deficits. According to the criteria established by Hadden et al., electrodiagnostic studies showed a demyelinating pattern in four patients and axonal neuropathy pattern in two. Early motor conduction block at intermediate nerve segments was found in five patients.
Conclusions: GM1 and GalNAc-GD1a may form a complex in the axolemma at nodes of Ranvier or paranodes of the motor nerves, and may be a target antigen in pure motor Guillain-Barré syndrome, especially in the form of acute motor conduction block neuropathy.