Changes in thyrotropin binding inhibitor immunoglobulin (TBII) concentration before and after various treatments in a patient with infiltrative Graves' ophthalmopathy.

Abstract

In a patient with active Graves' disease an infiltrative ophthalmopathy developed during antithyroid drug therapy. Her eye symptoms were effectively treated with a large dose of prednisolone (PD), plasma exchanges (PE), cyclophosphamide, orbital irradiation, antithyroid drug and a supplemental dose of triiodothyronine. Before, during and after these treatments thyrotropin binding inhibitor immunoglobulin (TBII) activities in a unit serum immunoglobulin (IgG) were measured after adjusting the IgG concentration by adding normal IgG. Relative TBII concentrations were calculated by extrapolating individual data on a standard curve constructed from serial dilutions of the most potent IgG. Approximately a 5 fold increase in the TBII concentration was observed during the 2 months of progression of the ophthalmopathy, while TBII activity revealed only a 13.3% increase. After treatment TBII concentrations decreased gradually showing a close relation with the severity of the eye symptoms. Every PE was found to remove 48.5 +/- 7.9 (s.e.m.) % of TBII. After PE TBII returned to the preexchange level very rapidly and then overshot it in 2 to 3 weeks. Sixty mg of PD failed to prevent the overshoot but a 100 mg initial dose of PD after 5 PEs inhibited it to some extent. The effectiveness of combined therapy with PE, PD and cyclophosphamide appeared to confirm a role of humoral factors in the pathogenesis of Graves' ophthalmopathy. Serial determinations of TBII in a relative concentration were considered quite useful in analyzing the effectiveness of treatment in Graves' ophthalmopathy.