Sarić Matutinović, M. (57211507979)M. (57211507979)Sarić MatutinovićDiana, T. (55805191700)T. (55805191700)DianaNedeljković Beleslin, B. (6701355427)B. (6701355427)Nedeljković BeleslinĆirić, J. (6601995819)J. (6601995819)ĆirićŽarković, M. (7003498546)M. (7003498546)ŽarkovićKahaly, G.J. (7005506174)G.J. (7005506174)KahalyIgnjatović, S. (55901270700)S. (55901270700)Ignjatović2025-06-122025-06-122022https://doi.org/10.1007/s40618-021-01652-yhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85111550749&doi=10.1007%2fs40618-021-01652-y&partnerID=40&md5=88b0d4f84b3a92375f3cd019efe7d68bhttps://remedy.med.bg.ac.rs/handle/123456789/3920Purpose: Thyrotropin receptor autoantibodies (TSH-R-Ab) are heterogeneous in their biological function and play a significant role in the pathophysiology of both Graves’ disease and Graves’ orbitopathy (GO). The clinical significance and utility of determining functional TSH-R-Ab in a Serbian collective were evaluated. Methods: 91 consecutive patients with GO were included in this study. Total TSH-R-Ab concentration, referred to as TSH-R binding inhibitory immunoglobulins (TBII) was detected using a competitive-binding immunoassay. Stimulating and blocking TSH-R-Ab (TSAb and TBAb) were measured with cell-based bioassays. Results: Stimulating TSAb activity and TBII positivity were detected in 85 of 91 (93.4%) and 65 of 91 (71.4%) patients with GO (P < 0.001). Blocking TBAb activity was observed in only one patient who expressed dual stimulating and blocking TSH-R-Ab activity. The sensitivity rates for differentiating between clinically active versus inactive and mild versus moderate-to-severe GO were 100% and 100% for TSAb, respectively. In contrast, these were 82% and 87% only for TBII. Seven of eight (87.5%) and one of eight (12.5%) euthyroid patients with GO were TSAb and TBII positive, respectively (P < 0.031). TSAb serum levels significantly predicted GO activity compared to TBII (odds ratio, OR, 95%CI: 3.908, 95%CI 1.615–9.457, P = 0.003; versus 2.133, 0.904–5.032, P = 0.084, univariate analysis; and OR 4.341, 95%CI 1.609–11.707, P = 0.004; versus 2.337, 0.889–6.145, P = 0.085 multivariate analysis). Conclusion: Stimulating TSAb are highly prevalent in patients with GO and show superior clinical characteristics and predictive potential compared to the traditionally used TBII. © 2021, Italian Society of Endocrinology (SIE).Autoimmune thyroid diseasesBioassayDiseaseFunctional thyrotropin receptor antibodiesGravesGravesOrbitopathyStimulatory antibodies