[Antiganglioside antibodies in motor neuron disease and motor dominant neuropathies]

Serum antiganglioside antibodies were investigated in motor neuron disease (MND) and in chronic or acute immune-mediated motor-dominant neuropathies. IgM antibody binding to GM1 and GA1, reacting with Gal beta 1-3GalNAc epitope, was seen in 5 out of 26 cases of MND. IgM antibody binding to Gal beta 1-3GalNAc epitope was also detected in 3 out of 3 cases with motor dominant neuropathy with multifocal conduction block (MNMCB). The IgM M-protein in a case with motor dominant neuropathy bound to GM1, GD1b, GM2 but not to GA1. This M-protein may recognize carbohydrate epitope including sialic acid. Antiganglioside antibodies were detected in 11 out of 16 cases with Guillain-Barré syndrome (GBS). Among them, anti-GM1 antibodies were detected in 6 cases. Gal beta 1-3GalNAc epitope was recognized in 3 cases, and GM1 was monospecifically recognized in 3 cases. Thus the binding specificities of anti-GM1 antibody in motor dominant neuropathies were varied. The titers of anti-GM1 antibodies in 1 case with MNMCB and in 6 cases with GBS were more than 1:160, whereas those in MND were less than 1:80. The high titers of antibody in MNMCB and GBS decreased in association with clinical improvement, suggesting that they are closely related with the disease process. Although the titers are low, anti-GM1 antibody in MND may give us a clue to elucidate the pathogenetic mechanisms of this intractable disease.