ELECTRODIAGNOSTIC FINDINGS RELATED TO ANTI-GM1 AND ANTI-GQ1B ANTIBODIES IN GUILLAIN-BARRE-SYNDROME

Antibodies against the gangliosides GM1 and GQ1b may induce conduction failure in mice. To investigate their possible site of action in the Guillain-Barre syndrome (GBS), we studied the relation between serum a nti-GM1 and anti-GQ1b antibodies and electromyography in 124 GBS patie nts. Anti-GM1 antibodies were found in 22 (18%) and anti-GQ1b antibodi es in 5 (4%) patients. Anti-GM1 antibodies were associated with low di stal compound muscle action potential amplitudes and relatively high c ompound sensory nerve action potential (CSNAP) amplitudes. In none of the patients with anti-GQ1b antibodies could CSNAPs be detected, Patie nts with anti-GM1 and anti-GQ1b antibodies were heterogenous with resp ect to electrodiagnostic features exclusive for demyelination or axona l degeneration, although the anti-GM1 positive patients tended to have more axonal degeneration, In conclusion, electromyographic studies in dicate selective and more severe damage of motor nerves in patients wi th anti-GM1 antibodies, while patients with anti-GQ1b antibodies have more severe damage of sensory nerves. These antibodies may interfere w ith the electrophysiologic properties of different nerve fibers and th ereby contribute to the clinical heterogeneity in GBS. (C) 1997 John W iley & Sons, Inc.