ELISA-type titertray assay of IgM anti-GM1 autoantibodies.

We report an ELISA-type titertray assay for autoantibodies against the ganglioside GM1. Trays were coated with ganglioside GM1 and reacted with patients' sera; bound IgM was detected with rabbit antibody to human IgM. High-titer serum from a patient was used as calibrator, another patient's serum as the positive control, and the GM1-specific cholera toxin as the control for GM1 coating. Regression curves of serum titers obtained from different patients were linear and parallel. Intra- and interassay CVs were 4.0-7.8% and 5.5-16%, respectively. We detected antibodies at a titer of 1:250 in normal subjects. Analytical specificity of the calibrator serum against GM1 was demonstrated by immune thin-layer chromatography. Anti-GM1 antibodies were increased in patients with chronic inflammatory demyelinating polyradiculoneuropathy (P < 0.002) or multiple sclerosis (P < 0.01). In Guillain-Barré syndrome, preliminary longitudinal studies showed a decrease in anti-GM1 titer that was related to clinical recovery.