Comparison Between Thyroid Stimulating Immunoglobulin and TSH-Receptor Antibodies in the Management of Graves’ Orbitopathy

Abstract

Introduction TSH-receptor antibodies (TRAb) targeting the TSH receptor (TSH-R) induce hyperthyroidism in Graves´ disease (GD). Graves´ orbitopathy (GO) is influenced by a stimulation of the TSH-R in the orbita. GO has been, among other factors, linked to high TRAb levels. Thyroid stimulating immunoglobulins (TSI) is a relatively new method for assessing TSH-receptor antibodies. The aim of this study was to investigate the role of TSI in management of GO. Materials and methods Patients with newly diagnosed GD (n=30, median age 55 years (range 35-72), 29 women) received pharmacological therapy (methimazole + thyroxine) up to 24 months. GO was identified by clinical signs and symptoms. Eleven patients had GO at diagnosis and another six developed GO during treatment. Blood samples for TSI and other thyroidal biomarkers were obtained at baseline and at five occasions during the 24-month follow-up. 22 subjects completed the drug regimen without surgery or radioiodine treatment. Results At baseline, TSI was highly correlated with TRAb (rs=0.64, p<0.001), and both assays similarly correlated to fT3 values. TSI and TRAb did not differ significantly between GO and non-GO patients neither for visit v1 (n=30, 17 GO during the whole study), nor at follow-up (n=22, 12 GO during the whole study). During follow-up, levels of TSI and TRAb decreased and normalized in both groups. Conclusion The present study does not support any added benefit of TSI compared to TRAb for prediction and management of GO.

High Diagnostic Accuracy of Thyroid-Stimulating Hormone (TSH) Receptor Antibodies in Distinguishing Graves’ Disease and Subacute Thyrotoxicosis in the Indian Population

“…Recent studies have also demonstrated the utility of a few newer methods for the measurement of TSHrAb such as one-step third-generation radioimmunoassay and dot-blot method are useful, albeit with modestly lower diagnostic accuracy of the latter method [24,25]. Thyroid stimulating antibody (TSI), the best method for assessment of autoimmunity in Graves' disease, may have better diagnostic performance in diagnosing Graves' disease, and offer a better prediction of thyroidassociated orbitopathy and response to antithyroid therapy [26][27][28]; however, the reports are variable and advantages in clinical practice are minimal [29]. Moreover, this assay is not currently available in India.…”

Epidemiology of thyroid-stimulating immunoglobulin in recent-onset symptomatic thyroid eye disease

“…34 On the contrary, Khamisi et al did not show additional benefit of using TSI compared to the conventional TRAb assay in a Japanese study. 35 A systematic review revealed that the discrepancies in the relationship between TBII and TSI could be due to ethnic differences. The relationship between TED and TBII seems to be stronger in Asian patients.…”

Thyroid stimulating immunoglobulin concentration is associated with disease activity and predicts response to treatment with intravenous methylprednisolone in patients with Graves’ orbitopathy

“…Research herein has primarily focused on the use of different assays as a biomarker for disease activity and severity, showing that TSI bioassays, outperform TBII assays (4,5,7,(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). So far, only a limited number of studies investigated the applicability of the bridge-based TSI binding assay as a biomarker for disease activity and severity in GO, with conflicting results (26)(27)(28)(29)(30). Although identifying patients with active disease is important, it may be even more relevant to identify patients who will not respond to intravenous methylprednisolone (IVMP).…”