Anti-thyroid-stimulating hormone receptor antibodies determined by second-generation assay

Background: The aim of our study was to determine the frequency of anti-thyroid-stimulating hormone (TSH) receptor antibodies (TRAb) in Tunisian patients with Graves' disease (GD) and to compare the validity of TRAb to that of thyroperoxidase (TPO-Ab) and thyroglobulin antibodies (TG-Ab). Methods: ELISA was used to determine the frequency of TRAb, TPO-Ab and TG-Ab in sera of 190 patients with GD. Patients were divided into four groups: those with untreated active GD (group A, n=71), those receiving treatment with anti-thyroid drugs (group B, n=85), those in relapse (group C, n=15) and those in remission (group D, n=19). Sera of 100 healthy blood donors served as controls. Results: The sensitivity of TRAb for the diagnosis of GD (95.8%) was significantly higher than that of TPO-Ab (73.2%) and TG-Ab (42.2%) (p =0.0005 and p<10 -7 , respectively). The positive rate for TRAb was lower in group B than in group A (70.6% and 95.8%, respectively; p=0.0001). The levels of TRAb were significantly higher in group A than in group B (mean 30.1 and 14.2 IU/L, respectively; p=0.006). Conclusions: TRAb, but neither TPO-Ab nor TG-Ab, is valuable in the diagnosis and management of patients with GD.