Low Frequency of Pendrin Autoantibodies Detected Using a Radioligand Binding Assay in Patients With Autoimmune Thyroid Disease

Abstract

Pendrin is a transmembrane protein located at the apical end of the thyrocyte in which it mediates the efflux of iodide through the thyroid follicular cell. Recently pendrin was described as a significant antibody target in Japanese patients with Graves' disease (GD) or autoimmune hypothyroidism (AH) using an immunoblotting assay. However, a subsequent study failed to verify this in autoimmune thyroid disease (ATD) patients of Tunisian origin. The aim of the current study was to evaluate a UK population of patients with ATD for the presence of pendrin autoantibodies using a novel radioligand binding assay (RBA). Sera from 71 GD and 66 AH patients and 28 healthy controls were evaluated for pendrin autoantibody reactivity in RBAs. The results indicated that 8.8% of patients with ATD (9.9% GD and 7.6% AH) were positive for pendrin autoantibodies. Overall, the frequency of pendrin autoantibodies did not differ significantly between the ATD patient cohorts and the healthy control group: P = .186 and P = .317 for GD and AH patients, respectively. Pendrin autoantibodies, detected using a novel RBA, are not widely prevalent in UK patients with ATD, nor do they differ in frequency between GD and AH. These autoantibodies are therefore unlikely to be a useful marker for disease diagnosis, although the role that pendrin may play as an autoantigen in the initiation or maintenance of thyroid autoimmunity remains to be established.