Search of reference biomarkers reflecting orbital tissue remodeling in the course of Graves' Orbitopathy.

INTRODUCTION: Graves' orbitopathy (GO) is a complication in Graves' disease (GD) that causes disfigurement and sometimes blindness. The pathogenesis of GO remains unknown, while its symptoms demonstrate dependence between the thyroid gland and the orbit. The ongoing inflammatory process in retrobulbar tissue results in its remodeling characterized by increased volume of the orbital contents involving adipose tissue, with fibrosis and adipogenesis as predominant features. This study was aimed at the immunohistochemical verification of potential contribution and correlation between orbital expressions of IGF-1R, CD34, Foxp-3, PPAR-gamma and CD4, CD68, TGF-beta, FGF-beta in severe and mild (long-lasting) GO. MATERIAL AND METHODS: Forty-one orbital tissue specimens - 22 patients with severe GO, 9 patients with mild GO and 10 patients undergoing blepharoplasty as a control group - were processed by routine immunohistochemistry. RESULTS: Increased IGF-1R, CD34 and Foxp-3 expression was found in both severe and mild GO, yet a significant correlation between CD34 and CD4, CD68, TGF-beta, FGF-beta expressions was observed in long-lasting GO. CONCLUSIONS: CD34 expression is proposed to be the marker of orbital tissue remodeling in the course of mild GO.