[Autoantibodies in Guillain-Barré Syndrome]

Serum antibodies against glycolipids, mainly gangliosides, are detected in about 60% of patients with Guillain-Barré syndrome (GBS) and its variants. Anti-glycolipid antibodies play a crucial role in the pathogenic mechanisms of GBS. The antibody titer is the highest in the acute phase and decreases gradually. Molecular mimicries occur between the glycolipids and surface molecules on the infectious agents. Clinical subtypes of GBS are related to the antigenic specificities of the antibodies. The distribution of gangliosides in peripheral nervous tissues could explain the different clinical manifestations. The anti-GQ1b antibody is detected in 80-90% of patients with Fisher syndrome characterized by ophthalmoplegia. GQ1b is localized in the paranodes of the human cranial nerves innervating the extraocular muscles. This is consistent with the clinical association between the anti-GQ1b antibody and ophthalmoplegia. The anti-GM1 antibody is associated with acute motor axonal neuropathy, whereas the anti-GD1b antibody is detected in acute sensory ataxic neuropathy. GBS animal models sensitized by gangliosides, such as GM1 or GD1b, develop monophasic peripheral neuropathies. In the animal models, disruption of molecule clusters and deposition of complement products were observed in the nodal and paranodal regions. Clinical and experimental data suggest complement-mediated pathogenic mechanisms triggered by anti-glycolipid antibodies in GBS.