Role of eye muscle antibody measurement in diagnosis of thyroid-associated ophthalmopathy: a laboratory update.

Objective: To review the current role of measurement of serum eye muscle antibodies in thyroid-associated ophthalmopathy (TAO).

Methods: We conducted laboratory studies to determine the prevalences of serum autoantibodies reactive with eye muscle antigens in patients with active and inactive TAO, Graves' hyperthyroidism, and Hashimoto's thyroiditis as well as in normal subjects.

Results: The two antigens most often recognized in immunoblotting with crude human or porcine eye muscle membranes by serum autoantibodies in patients with TAO are eye muscle membrane proteins of 55 and 64 kd.

Role of the eye muscles in thyroid eye disease: identification of the principal autoantigens.

Thyroid-associated ophthalmopathy (TAO) is a progressive orbital disorder associated with Graves' hyperthyroidism and, less often, Hashimoto's thyroiditis in which autoantibodies react with orbital antigens and lead to exophthalmos and eye muscle inflammation. Eye muscle (EM) membrane proteins initially reported as 55 and 64 kd are the best markers of ophthalmopathy. The "64-kd protein" is now shown to be the flavoprotein subunit of mitochondrial succinate dehydrogenase and to have a correct molecular weight of 67 kd.