PLA2R: The Same Target Antigen of Idiopathic Membranous Nephropathy and Hashimoto's Thyroiditis?

Background: Autoimmune thyroid disease associated nephropathy was identified 40 years ago; however, the cause of the disease remains unknown. Methods: Phospholipase A2 receptor (PLA2R) antibodies was assayed quantitatively in the serum of patients with Graves' disease, Hashimoto's thyroiditis (HT), idiopathic membranous nephropathy (IMN) and normal controls by time-resolved fluoroimmunoassay. PLA2R antigens were immunohistochemically analyzed in the thyroid tissue with Graves' disease and HT, as well as the nephridial tissue with IMN. Findings: The concentration of phospholipase A2 receptor (PLA2R) antibodies in the serum of normal controls, patients with Nodular goiter, Graves' disease and HT, as well as patients with IMN was 1.13 ± 0.43 mg/L, 1.07 ± 0.22mg/L, 2.12 ± 2.11mg/L, 8.07 ± 4.74mg/L, and 15.91 ± 19.50mg/L, respectively. The concentration of PLA2R antibodies in the serum and its areas under the curve of ROC in HT and IMN cases increased significantly. The immunohistochemistry revealed that the tissues of the patients with HT were obviously stained, with a positive rate of 66.67%. Interpretation: PLA2R may be a pathogenic target antigen for HT, and the production of anti-PLA2R antibodies may cause autoimmune thyroid disease associated nephropathy.  Funding Statement: Clinical Medical Science fund of Jiangsu Province (No. BL2014022), Jiangsu Maternal and Child Health Research Project (FRC201741), and Wuxi City Science and Education Project (ZDRC006) supported the study. Declaration of Interests: All Authors declare no competing financial interests. Ethics Approval Statement: Patients from Jiangsu Jiangyuan Hospital and the Wuxi People’s Hospital affiliated to Nanjing Medical University, were enrolled. The study protocol was approved by the medical ethics committee of Jiangsu Jiangyuan Hospital and Affiliated Wuxi People's Hospital of Nanjing Medical University.