title: Myasthenia gravis muscle antibodies examined by ELISA: IgG and IgM antibodies characterize different patient subgroups.
abstract: Sera from 90 myasthenia gravis (MG) patients were examined for antibodies against skeletal muscle citric acid extract (CA) antigens by ELISA and indirect haemagglutination (IHA). 31% (ELISA) and 24% (IHA) of the sera were positive, and the results of the two tests were in good agreement. 18 of 28 patients positive in ELISA had IgG CA-antibodies, 10 had IgM and 3 IgA CA-antibodies. The patients with IgG antibodies had a high mean age of MG disease onset, and 9/14 thymectomized patients had a thymoma. Patients with IgM CA-antibodies had a much lower age of onset and 4/5 thymectomized patients had thymus hyperplasia. IgM antibody positive patients had a long disease duration, indicating that they produce IgM antibodies for an indefinite period of time without switching to IgG antibody production.
authors.affiliation: Broegelmann Research Laboratory for Microbiology, University of Bergen, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Hofstad
authors.forename: E
authors.initials: E
authors.lastname: Ulvestad
authors.forename: N E
authors.initials: NE
authors.lastname: Gilhus
authors.forename: R
authors.initials: R
authors.lastname: Matre
authors.forename: J A
authors.initials: JA
authors.lastname: Aarli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009124:Muscle Proteins / Q000276:immunology*; D009132:Muscles / Q000276:immunology*; D009157:Myasthenia Gravis / Q000175:diagnosis / Q000276:immunology*; D013945:Thymoma / Q000175:diagnosis / Q000276:immunology; D013950:Thymus Gland / Q000473:pathology; D013952:Thymus Hyperplasia / Q000175:diagnosis / Q000276:immunology; D013953:Thymus Neoplasms / Q000175:diagnosis / Q000276:immunology
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D009124:Muscle Proteins