[Fisher syndrome and anti-GQ1b antibody].

Serum anti-GQ1b IgG antibody is specifically detected in almost all the patients with Fisher syndrome and those with Guillain-Barré syndrome with ophthalmoplegia in the acute phase. An anti-GQ1b mouse monoclonal antibody immunostained the paranodal regions of the extramedullary portion of the human oculomotor, trochlear and abducens nerves. Such immunostaining was not observed in the other cranial and peripheral nerves. Anti-GQ1b IgG antibody may be involved in the pathogenetic mechanism of ophthalmoplegia in Fisher syndrome and Guillain-Barré syndrome by binding to the paranodal regions of the oculomotor, trochlear and abducens nerves. Investigation of serum anti-GQ1b antibody is considered to be a useful diagnostic marker in Fisher syndrome and Guillain-Barré syndrome with ophthalmoplegia.