title: Neuropathy and anti-MAG antibodies without detectable serum M-protein.
abstract: Anti-MAG IgM antibodies were detected by ELISA in a patient with slowly progressive peripheral neuropathy. Serum IgM content was normal, and no M-protein was detected by serum protein electrophoresis, immunoelectrophoresis, or immunostaining. By immunoblot analysis, the anti-MAG antibodies were IgMk; they reacted with human and bovine MAG but not with mouse MAG. The data suggest that there was an anti-MAG IgM M-protein in concentration too low to be detected by conventional techniques. Tests for anti-MAG antibodies should be done in patients with slowly progressive neuropathy of unknown etiology, even in the absence of detectable serum M-protein.
mesh_terms: D000368:Aged; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis*; D001798:Blood Proteins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D008297:Male; D009185:Myelin Proteins / Q000276:immunology*; D018992:Myelin-Associated Glycoprotein; D010523:Peripheral Nervous System Diseases / Q000097:blood / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D001798:Blood Proteins; D007075:Immunoglobulin M; D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein