T and B cell reactivity to extraocular and skeletal muscle in Graves' ophthalmopathy

We have sought human eye muscle membrane binding antibodies in patients with Graves' ophthalmopathy using an enzyme-linked immunoassay. Antibodies were found in patients with thyroid autoimmunity irrespective of eye signs, and binding correlated closely (r = 0.94) with binding to skeletal muscle, showing that these antibodies are not site-specific. T cells from patients with thyroid autoimmunity proliferated in response to eye muscle, but again this was not specific for eye muscle or the presence of ophthalmopathy. No single antigen was responsible for inducing proliferation. These results fail to confirm a recent report of eye muscle membrane binding antibodies in a high proportion of patients with ophthalmopathy, and suggest instead that T and B cell autoreactivity to striated muscle antigens is a frequent feature of autoimmune thyroid disease, unlikely to be directly related to eye disease.