title: Paraneoplastic myasthenia gravis: detection of anti-MGT30 (titin) antibodies predicts thymic epithelial tumor.
abstract: It has been suggested that antibodies against non-acetylcholine receptor proteins of striated muscle are markers of the presence of a thymic epithelial tumor in patients with myasthenia gravis (MG). These antibodies may be measured using an immunofluorescence assay against striated muscle (anti-STR) or an ELISA with a recombinant 30-kd titin fragment (anti-MGT30). To directly compare anti-STR with anti-MGT30, we examined the sera of 276 consecutive patients with known or suspected MG. Definite diagnoses and thymic histology, if available, were correlated with the antibody assays. Of the 276 patients, 164 had MG. Thymic histology was obtained in 44 patients: 18 had lymphofollicular hyperplasia, 13 thymic epithelial tumors, 8 atrophy, and 5 were normal. When compared with anti-STR, anti-MGT30 showed a sensitivity of 69% (STR 77%), specificity of 100% (STR 56%, p = 0.026), negative predictive value of 82% (STR 77%), and positive predictive value of 100% (STR 56%, p = 0.003) for the identification of a thymic epithelial tumor versus thymic hyperplasia. We conclude that the anti-MGT30 ELISA is better than the anti-STR immunofluorescence assay for the diagnosis of paraneoplastic MG.
authors.affiliation: Departments of Neurology, Klinikum Grosshadern, LMU, München, Germany.
authors.forename: R D
authors.initials: RD
authors.lastname: Voltz
authors.forename: W C
authors.initials: WC
authors.lastname: Albrich
authors.forename: A
authors.initials: A
authors.lastname: Nägele
authors.forename: F
authors.initials: F
authors.lastname: Schumm
authors.forename: M
authors.initials: M
authors.lastname: Wick
authors.forename: A
authors.initials: A
authors.lastname: Freiburg
authors.forename: M
authors.initials: M
authors.lastname: Gautel
authors.forename: H T
authors.initials: HT
authors.lastname: Thaler
authors.forename: J
authors.initials: J
authors.lastname: Aarli
authors.forename: T
authors.initials: T
authors.lastname: Kirchner
authors.forename: R
authors.initials: R
authors.lastname: Hohlfeld
mesh_terms: D001323:Autoantibodies / Q000097:blood; D064211:Connectin; D003943:Diagnostic Techniques, Neurological; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D008875:Middle Aged; D009124:Muscle Proteins / Q000276:immunology*; D009157:Myasthenia Gravis / Q000175:diagnosis / Q000209:etiology / Q000276:immunology*; D010257:Paraneoplastic Syndromes / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology*; D011237:Predictive Value of Tests; D011494:Protein Kinases / Q000276:immunology*; D012680:Sensitivity and Specificity; D013953:Thymus Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000276:immunology
chemical_list: D001323:Autoantibodies; D064211:Connectin; D009124:Muscle Proteins; C577285:TTN protein, human; D011494:Protein Kinases