Levels of Thyroid Autoantibodies in Patients with Graves' Disease and Graves' Ophtalmopathy - Original Article

Abstract
Objective: Previous studies in patients with Graves' disease (GD) and Graves’ ophtalmopathy (GO) have focused mainly on the levels of TSH-receptor antibodies (TRAb). Our aim was to investigate the levels of TRAb, thyroid peroxidase (TPOAb) and thyroglobulin antibodies (TGAb) in patients with GD with and without GO.
Materials and Methods: 98 patients with GD were included in this retrospective study-76 women and 22 men. Thirty-nine patients had manifested GO - 28 women, 11 men. The serum levels of thyroid stimulating hormone (TSH) and free thyroxine (fT4) were measured by a chemiluminescence assay; TPOAb and TGAb - by an electrochemiluminescence method, and TRAb - by an enzymatic-substrate method-ELISA.
Results: Median serum levels of TSH and fT4 were 0.079 IU/l and 37.7 pmol/l in patients with GD + GO versus 0.420 IU/l and 23.2 pmol/l in patients with GD without GO (p=0.04 for TSH and p=0.02 for fT4). In GD + GO, we found higher levels of TRAb (22.1 versus 10.4 IU/L, p<0.001) and TGAb (412.5 vs. 190.6 IU/l, p<0.001), and lower levels of TPOAb (390.6 vs. 690.4 IU/l, p=0.001) than in GD alone. 
Conclusion: Higher levels of TGAb and TRAb, and lower levels of TPOAb are found in patients with GD with GO compared to patients without ophtalmopathy. These findings might open new perspectives in studying the pathogenesis of GO.