Endocrine Abstracts

Context: Pendrin is a transmembrane protein located at the apical end of the thyrocyte where 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 or autoimmune hypothyroidism using an immunoblotting assay. However, a subsequent study failed to verify this in autoimmune thyroid disease patients of Tunisian origin.

Objective: The aim of the current study was to evaluate a UK population of patients with autoimmune thyroid disease for the presence of pendrin autoantibodies using a novel radioligand binding assay.

Results: Sera from 71 Graves’ disease and 66 autoimmune hypothyroidism patients and 28 healthy controls were evaluated for pendrin autoantibody reactivity in radioligand binding assays. The results indicated that 7/71 (9.9%) Graves’ disease and 5/66 (7.6%) autoimmune hypothyroidism patient sera, respectively, were positive for pendrin autoantibodies. Overall, the frequency of pendrin autoantibodies did not differ significantly between the autoimmune thyroid disease patient cohorts and the healthy control group: P=0.186 and 0.317 for Graves’ disease and autoimmune hypothyroidism patients, respectively.

Conclusion: Pendrin autoantibodies, detected using a novel radioligand binding assay, are not widely prevalent in UK patients with autoimmune thyroid disease, nor do they differ in frequency between Graves’ disease and autoimmune hypothyroidism. 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.