Glycosaminoglycan antibodies in endocrine ophthalmopathy

An increased accumulation of glycosaminoglycans (GAG) in the orbita has been reported in endocrine ophthalmopathy (EO). In this study we investigated whether antibodies directed against GAG are present in the sera of 52 EO patients and 47 healthy controls. Three out of 52 patients exhibited low titers of antinuclear antibodies and all patients were negative for antibodies against extractable nuclear antigens. Isotype IgG antibodies were detected by means of an ELISA using hyaluronic acid and dermatan sulfate as antigens. Values were expressed as optical density at 405 nm. In comparison to the control group (0.445, 0.364, 0.588; median, 25th, 75th percentile) significantly (p < 0.001) higher hyaluronic acid antibody levels were found in EO patients (0.626, 0.473, 0.801). Untreated patients had significantly higher hyaluronic acid antibody values compared to controls (0.770 vs 0.437, median, p < 0.005). Thyroid status or antithyroid treatment did not influence binding of hyaluronic acid antibodies. When screening for dermatan sulfate antibodies no such difference could be observed between patients and controls. Thus, the detection of GAG antibodies in EO patients emphasizes the important role of glycosaminoglycans in the pathogenesis of thyroid eye disease.