Thyroid Stimulating Antibodies Are Highly Prevalent in Hashimoto's Thyroiditis and Associated Orbitopathy

Thyroid-associated orbitopathy (TAO) rarely occurs in patients with Hashimoto's thyroiditis (HT).There is evidence that TSH receptor stimulating antibodies (TSAb) play a role in the pathogenesis of TAO. In this report, the prevalence of TSAb in HT patients with and without TAO was studied.This is a longitudinal observational study.The study took place in an academic joint thyroid-eye clinic.A total of 1055 subjects were included.TSAb was measured with a Food and Drug Administration-cleared bioassay that uses Chinese hamster ovary cells expressing a chimeric TSH receptor and a cAMP response element-dependent luciferase. Results of TSAb activity were reported as percentage of specimen-to-refe…