Fibroblasts expressing the thyrotropin receptor overarch thyroid and orbit in Graves' disease.

Context: Graves' disease (GD) is a systemic autoimmune syndrome comprising manifestations in thyroid and orbital connective tissue. The link between these two tissues in GD eludes our understanding. Patients with GD have increased frequency of circulating monocyte lineage cells known as fibrocytes. These fibrocytes infiltrate orbital connective tissues in thyroid-associated ophthalmopathy and express functional TSH receptor (TSHR). Objective: The aim of the study was to identify and characterize CD34+ fibrocytes in thyroid tissue. Design/Setting/Participants: Patients undergoing surgical thyroidectomy at two academic medical centers were recruited to the study. Main Outcome Measures: We performed immunohistochemistry, flow cytometry, real-time PCR, cytokine-specific ELISA, and cell differentiation. Results: CD34+ColI+CXCR4+TSHR+ cells can be identified in situ in thyroid tissue from donors with GD, Hashimoto's thyroiditis, or in normal-appearing tissue. Thyroid fibroblasts cultivated from these glands exp...