Antiganglioside antibodies

Anti-GD3 antibodies have been found in association with specific forms of Guillain–Barré syndrome. In vivo studies of isolated anti-GM1 and GD3 antibodies indicate the antibodies can interfere with motor neuron function.[2] Anti-GD1a antibodies were highly associated acute motor axonal neuropathy while high titers of anti-GM1 were more frequent indicating that GD1a possibly targets the axolemma and nodes of Ranvier[3] most of the Ab+ patients had C. jejuni infections. Patients with Anti-GalNAc-GD1a antibodies were less common but had more severe disease (rapidly progressive, predominantly distal weakness).[4]

Levels of anti-GM1 antibodies are elevated in patients with various forms of dementia.[5] Antibodies levels correlate with more severe Guillain–Barré syndrome.[6] Levels of anti-GM1 antibodies are especially elevated in patients with prodromal diarrhea.[7] Titers to GM1 in other diseases (rheumatoid arthritis, primary Sjögren's syndrome and systemic lupus erythematosus) was also elevated.[8] Additionally highly significant association was found with rheumatoid arthritis and peripheral neuropathies.[9] Conflicting evidence suggests no significant elevation in motor neuron neuropathy but marginally elevated IgA in sensory neuron neuropathies.[10] The autoimmune role of anti-GM1 is still unclear. Multifocal motor neuropathy (MMN) with conduction block is closely related to CIDP (chronic inflammatory demyelinating polyneuropathy). Anti-GM1 antibodies are positive in around 80% of cases. MMN will present with asymmetrical motor neuropathy where reflexes are usually preserved (or slightly increased), affecting upper limb more than lower limb. MMN is potentially treatable with immunomodulation.

Anti-GQ1b are found in Miller-Fisher syndrome. This presents with the classical triad of ataxia, areflexia and ophthalmoplegia. Studies of these antibodies reveal large disruption of the Schwann cells.[11] Anti-GQ1b IgG levels were elevated in patients with ophthalmoplegia in Guillain–Barré syndrome[7]

Antibodies to a GM1 epitope as well as to one with the GT1a or GD3 epitope were found in different strains of Campylobacter jejuni[13] and patients with Guillain–Barré syndrome have a high occurrence of C. jejuni infection.[14] Many studies indicate that C. jejuni may be causative for a subset of some forms of neuropathies.

Antibodies to ganglioside are found to be elevated in coeliac disease.[15] Recent studies show that gliadin can cross-link to gangliosides in a transglutaminase independent manner, indicating that gliadin specific T-cell could present these antigens to the immune system.[16]