DISEASE

Neuropathy – unclear/Guillain-Barré syndrome

Polyneuropathy where the cause is unknown or is suspected to be autoimmune. Gangliosides are a group of glycolipids that contain sialic acid and that occur in the nervous system. They are integrated in cell membranes, where they have a ceramide tail in the lipid bilayer and an oligosaccharide part, which protrudes and is accessible for antibodies. Of the many gangliosides that are known it is mainly GM1, asialo GM1, GQ1b, GD1a, and Gd1b that are of immunological interest in peripheral nerve diseases. Antibodies against these antigens, which often crossreact, are in some cases suspected of having a pathogenic role. IgM antibodies against GM1 and asialo GM1 are found with high frequency in multifocal motor neuropathy with conduction block (MMN), an important differential diagnosis of ALS. IgG antibodies against these gangliosides are found in patients with Guillain-Barré syndrome, mostly in the axonal form (AMAN) that can be triggered by Campylobacter jejuni.

Indications: Polyneuropathy where the cause is unknown or is suspected to be autoimmune.

Miller Fisher syndrome, with various degrees of ophthalmoplegia, ataxia and are flexia, is a variant of Guillain-Barré syndrome, where IgG antibodies against the ganglioside GQ1b occur with a very high frequency. IgM antibodies against this antigen are often detected in a special form of sensory atactic polyneuropathy with an M component of IgM class. (CANOMAD) IgG antibodies against GD1a occur in Guillain-Barré syndrome, in particular in the motor axonal form. IgM antibodies against GD1b are found in MMN and CANOMAD. Antibodies against myelin-associated glycoprotein (MAG) also bind to the carbohydrate part of the myelin protein P0 and SPGP. High titres of IgM antibodies against this antigen are very often associated with sensory polyneuropathy. Anti-MAG activity is detected in half the patients with an M component of IgM class.