Human retroocular fibroblasts in vitro: A model for the study of graves’ ophthalmopathy

Orbital connective tissue and extraocular muscles are histologically abnormal in patients with Graves’ ophthalmopathy (GO). Although extraocular muscles have been extensively studied as a target for autoimmune attack in the disease, no system has been available to study retroocular fibroblasts in GO. We developed a technique to isolate fibroblasts from minced explants of connective tissue removed in the course of transantral orbital decompression surgery for GO. Postmortem specimens from individuals without evidence of thyroid disease were obtained from the same anatomical site. Confluent cells could be passaged at least 10 times with stable morphology and frozen with greater than 75% viability. An enzyme-linked immunosorbent assay was used to study the in vitro binding of serum immunoglobulin G (IgG) to these cells. We found no difference in the degree of specific binding between GO cells and cells from normal individuals. However, there was significantly greater binding of IgG from GO sera than of that from normal serum to retroocular GO fibroblasts. These results suggest that serum IgG autoantibodies against normal retroocular fibroblasts are present in some GO patients.