title: Repeated acetylcholine receptor antibody-concentrations and association to clinical myasthenia gravis development.
abstract: BACKGROUND
  We aimed to examine the longitudinal association between Myasthenia Gravis (MG) clinical severity and concentration of acetylcholine receptor (AChR)-antibodies to evaluate if AChR-antibody variations correlate to disease severity. A positive AChR-antibody test is specific for MG.
  
  
  METHODS
  All patients from western Norway who had two or more AChR- antibody tests in the period 1983-2013 were identified. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification was used to grade disease development. Multiple ordinal logistic regression analysis was used to estimate a possible predictive effect for AChR-antibody concentration on MGFA classification result.
  
  
  RESULTS
  In 67 patients two or more AChR-antibody tests with a corresponding MGFA-score were performed, with a total of 309 tests. 56 patients were treated with immunosuppressive drugs and 11 by pyridostigmine only. There was a positive association between concentration of AChR-antibodies and longitudinal MGFA-score for the subgroup with immunosuppressive treatment, but not for those treated with pyridostigmine only. This association between AChR-antibody concentration and MGFA score declined with increasing time since onset (p = 0.005 for the interaction of group×time×concentration).
  
  
  CONCLUSIONS
  For MG patients with immunosuppressive treatment, repeated AChR-antibody measurements give information about clinical development, and can therefore be of support in therapeutic decisions.
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: Anne Taraldsen
authors.initials: AT
authors.lastname: Heldal
authors.affiliation: Centre of Clinical Research, Haukeland University Hospital, Bergen, Norway; Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: Geir Egil
authors.initials: GE
authors.lastname: Eide
authors.affiliation: Department of Neurology, Haukeland University Hospital, Bergen, Norway.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Romi
authors.affiliation: Department of Neurology, Haukeland University Hospital, Bergen, Norway.
authors.forename: Jone Furlund
authors.initials: JF
authors.lastname: Owe
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Neurology, Haukeland University Hospital, Bergen, Norway.
authors.forename: Nils Erik
authors.initials: NE
authors.lastname: Gilhus
mesh_terms: D000906:Antibodies / Q000097:blood*; D005500:Follow-Up Studies; D006801:Humans; D007165:Immunosuppression Therapy; D009157:Myasthenia Gravis / Q000175:diagnosis* / Q000473:pathology; D011729:Pyridostigmine Bromide / Q000494:pharmacology; D011950:Receptors, Cholinergic / Q000276:immunology*; D012189:Retrospective Studies
chemical_list: D000906:Antibodies; D011950:Receptors, Cholinergic; D011729:Pyridostigmine Bromide