Expression of Thyrotropin Receptor, Thyroglobulin, Sodium-Iodide Symporter, and Thyroperoxidase by Fibrocytes Depends on AIRE

Context: CD34+ fibrocytes, bone marrow-derived progenitor cells, infiltrate orbital connective tissue in thyroid-associated ophthalmopathy, a manifestation of Graves' disease. In the orbit, they become CD34+ fibroblasts and coexist with native CD34− fibroblasts. Fibrocytes have been shown to express TSH receptor and thyroglobulin. Objective: The objective of the study was to determine whether a broader repertoire of thyroid protein expression can be detected in fibrocytes and whether a common factor is responsible. Design/Setting/Participants: Fibrocytes and fibroblasts were collected and analyzed from healthy individuals and those with Graves' disease in an academic clinical practice. Main Outcome Measures: Real-time PCR, Western blot analysis, gene promoter analysis, cell transfections, and flow cytometric cell sorting were performed. Results: We detect two additional thyroid proteins expressed by fibrocytes, namely sodium-iodide symporter and thyroperoxidase. The autoimmune regulator (AIRE) protein app...