Ocular Manifestations and Clinical Implications of Serum Immunoglobulin G4 Levels in Graves’ Ophthalmopathy Patients

Abstract

ABSTRACT Purpose To investigate the association between serum immunoglobulin G4 (IgG4) levels and laboratorial parameters. Moreover, the ocular manifestations were compared in Graves’ ophthalmopathy (GO) patients. Methods Fifty-seven GO patients and fifty sex- and age-matched euthyroid subjects were enrolled. Serum IgG4 and immunoglobulin G (IgG) levels, thyroid hormones and thyroid autoantibodies were measured in all participants. Ophthalmologic examinations were performed to GO patients. Results Serum IgG4 levels were increased in GO patients compared with euthyroid subjects (p<0.001). Multivariate analysis showed that TRAb levels were correlated with IgG4 levels in GO patients (β=1.45, p = 0.024). There were eight GO patients with IgG4 levels ≥ 135 mg/dL. They all had both eyelids swelling and the differences of HER were less than 2mm. Seven patients (7/8) showed bilateral symmetrical thickening of the extraocular muscles. Conclusions Bilateral symmetry of ocular manifestation was observed in GO patients with IgG4 levels ≥135 mg/dL. IgG4 levels may be helpful in monitoring GO and diagnosing a new subtype of GO.