Secretory IgA and lysozyme in tears of patients with Graves' ophthalmopathy

Using an enzyme linked immuno-assay (ELISA) and spectrophotometry, we determined levels of secretory IgA and lysozyme in tears of 69 patients with Graves' ophthalmopathy and 28 controls. The quantitative determination of secretory IgA and lysozyme in tears provided an impression of the functioning of the lacrimal gland in the two groups. An IgA/lysozyme ratio was calculated in both patients and controls as a parameter for the activity of the secretory IgA-producing plasma cells in the lacrimal gland. An increase in the IgA/ lysozyme ratio was observed in 23 patients (33%) and one control (3%). Half of the patients who had suffered from the disease for more than 5 years showed a raised IgA/lysozyme ratio. No correlation was found between the IgA/lysozyme ratio and the NOSPECS classification. Our findings suggest that the lacrimal gland is involved in the orbital condition produced by Graves' ophthalmopathy. In most cases the involvement occurs in patients with a long history of the disease.