Characterization of complement-fixing antibodies to peripheral nerve myelin in Guillain-Barré syndrome.

Complement-fixing antibodies to peripheral nerve myelin (anti-PNM Ab) can be detected in the serum of patients with Guillain-Barré syndrome (GBS). Kinetics of these antibodies can be correlated with the changing clinical course; the appearance of activation products of the terminal complement cascade in cerebrospinal fluid, serum, and peripheral nerve of patients with GBS; and the ability of GBS serum to mediate complement-dependent demyelination of myelinating cultures of rodent dorsal root ganglion. Some of the anti-PNM Ab in all GBS serum tested thus far bind a neutral glycolipid of human PNM and cross react with Forssman antigen, a cross-species antigen found in many infectious agents. Studies suggest that an IgM antibody in GBS patients that could be triggered by multiple infectious agents binds a surface determinant of a Forssman-like lipid of human PNM and participates in demyelination of peripheral nerve through the activation of complement.