The expression of Fcγ receptors in Hashimoto's thyroiditis

The pathophysiological mechanism underlying Hashimoto's thyroiditis (HT) is still unclear. Thyroglobulin antibody (TgAb) and thyroid peroxidase antibody (TPOAb) are diagnostic hallmarks of HT. These IgG antibodies regulate the balance of immunologic tolerance and autoimmunity via Fc gamma receptors (Fc gamma Rs). The aim of our study was to investigate the role of Fc gamma Rs in the pathogenesis of HT. The percentage of peripheral blood mononuclear cells (PBMCs) from HT patients bearing Fc gamma RII was significantly lower than that seen in healthy donors, and the mean fluorescence intensity (MFI) value of Fc gamma RII on PBMCs from HT patients was significantly higher. The percentage of PBMCs positive for Fc gamma RIII also was significantly higher in HT patients, and the percentage of B cells bearing Fc gamma RIIB in HT patients was significantly lower than that seen in healthy donors. Our study therefore provides evidence for Fc gamma Rs, especially Fc gamma RIIB, being involved in the pathogenesis of HT. (C) 2015 Elsevier Inc. All rights reserved.