A study of the binding of Graves' immunoglobulins to orbital antigens.

The binding of Graves' immunoglobulins to membranes of human eye muscle (HEM) and guinea pig Harderian gland (HG) were studied. The membrane fraction of 100,000 X g sediment was used for ELISA. Serum samples from 55 patients with Graves' ophthalmopathy were evaluated for binding to the membrane preparation. There was a higher binding to HG with the sera from the patients with Graves' ophthalmopathy than in the control group (p less than 0.01), but there was no difference in binding to HEM. Purification of IgG from sera improved binding to HG in both patients' (p less than 0.001) and control group (p less than 0.005). There was also an increase in percentage of positive responses obtained with IgG 48% vs serum samples 37%. In 23 out of 24 patients we found the thickening of extraocular muscles by A-scan ultrasonography. In these groups of patients and 3 others with malignant ophthalmopathy the binding of IgG preparation to HG was similar to control group. In all assays there was an overlap between patients with Graves' ophthalmopathy and control subjects, and a lack of relationship between the responses in ELISA and clinical or severity of ophthalmopathy.