title: High cut-off value of a chimeric TSH receptor (Mc4)-based bioassay may improve prediction of relapse in Graves' disease for 12 months.
abstract: There are scarce reports regarding a functional prognostic value of thyroid-stimulating autoantibody (TSAb) levels using a thyroid-stimulating hormone receptor chimera (Mc4) in Graves' disease (GD) in iodine sufficient area. The aim of this study was to investigate whether Mc4-TSAb can predict GD remission/relapse after antithyroid drug (ATD) treatment and to compare Mc4-TSAb with a binding assay using M22 monoclonal antibody (M22-TRAb) in GD patients. We retrospectively reviewed the results of M22-TRAb and Mc4-TSAb in GD patients treated with ATD for 12 months. GD patients who underwent ATD treatment for at least 12 months were included. We compared the predictive values of M22-TRAb and Mc4-TSAb for GD remission and relapse. Of the 92 patients, 60 (65.2%) achieved remission and 32 (34.8%) relapsed within 12 months. In receiver operating characteristic analysis, there were no significant differences in the area under the curves (AUCs) between Mc4-TSAb [AUC=0.79 (95% CI 0.69-0.89)] and M22-TRAb [AUC=0.69 (95% CI 0.58-0.81)]. The optimal predictive cut-off values of M22-TRAb and Mc4-TSAb were 2.23 IU/L and 230%, respectively. At a high Mc4-TSAb cut-off, the better specificity of 85.0% and positive predictive value (PPV) of 69.0% were shown compared with those at the best cut-off for M22-TRAb. In conclusion, a high cut-off for an Mc4 assay may improve the predictive value of relapse with superior specificity and PPV compared with M22-TRAb in treated GD.
authors: Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, 120-752, Republic of Korea.
authors: Sena
authors: S
authors: Hwang
authors: Dong Yeob
authors: DY
authors: Shin
authors: Mi Kyung
authors: MK
authors: Song
authors: Eun Jig
authors: EJ
authors: Lee
mesh_terms: D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use; D001681:Biological Assay; D005260:Female; D006111:Graves Disease / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics*; D006801:Humans; D018828:Immunoglobulins, Thyroid-Stimulating / Q000032:analysis; D008297:Male; D008875:Middle Aged; D050506:Mutant Chimeric Proteins / Q000235:genetics*; D011237:Predictive Value of Tests; D011379:Prognosis; D011989:Receptors, Thyrotropin / Q000235:genetics*; D012008:Recurrence; D012189:Retrospective Studies
chemical_list: D013956:Antithyroid Agents; D018828:Immunoglobulins, Thyroid-Stimulating; D050506:Mutant Chimeric Proteins; D011989:Receptors, Thyrotropin