title: Correlation between TSH receptor antibody assays and clinical manifestations of Graves' orbitopathy.
abstract: OBJECTIVE
  To investigate an association between the levels of serum thyroid-stimulating hormone (TSH)-receptor autoantibodies (TRAbs) and Graves' orbitopathy (GO) activity/severity scores, and compare the performance of three different TRAb assays in assessing the clinical manifestations of GO.
  
  
  METHODS
  Cross-sectional study. Medical records of 155 patients diagnosed with GO between January 2008 and December 2010 were reviewed. GO activity was assessed by clinical activity score (CAS) and severity graded with the modified NOSPECS score by a single observer. Serum TRAb was measured by three different methods: 1st generation thyrotropin-binding inhibitor immunoglobulin (TBII) assay (TRAb1st); 3rd generation TBII assay (TRAb3rd); and biological quantitative assay of thyroid-stimulating immunoglobulin (TSI) using Mc4-CHO cells (Mc4-CHO TSI assay). Results were correlated with scores of activity/severity of thyroid eye disease.
  
  
  RESULTS
  All three assays (TRAb1st, TRAb3rd, and Mc4-CHO TSI) yielded results that were significantly positively correlated with CAS (β=0.21, 0.21, and 0.46, respectively; p<0.05) and proptosis (β=0.38, 0.34, and 0.33, respectively; p<0.05). Mc4-CHO TSI bioassay results were significantly positively correlated with all GO severity indices (soft tissue involvement, proptosis, extraocular muscle involvement, and total eye score; β=0.31, 0.33, 0.25, and 0.39, respectively; p<0.05).
  
  
  CONCLUSIONS
  Mc4-CHO TSI bioassay was superior over the two TBIIs in assessing active inflammation and muscle restriction due to GO, whereas TBII assay would be sufficient for evaluation of patients with proptosis.
authors.affiliation: Department of Ophthalmology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Jang
authors.forename: Dong Yeob
authors.initials: DY
authors.lastname: Shin
authors.forename: Eun Jig
authors.initials: EJ
authors.lastname: Lee
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Choi
authors.forename: Sang Yeul
authors.initials: SY
authors.lastname: Lee
authors.forename: Jin Sook
authors.initials: JS
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D016466:CHO Cells; D003412:Cricetulus; D003430:Cross-Sectional Studies; D005260:Female; D049970:Graves Ophthalmopathy / Q000097:blood / Q000209:etiology* / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011989:Receptors, Thyrotropin / Q000097:blood / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D011989:Receptors, Thyrotropin
keywords: Graves’ orbitopathy; TSH-receptor autoantibody; disease activity; severity