Diagnostic implications of tear protein profiles

Concentrations of lysozyme, lactoferrin, ceruloplasmin, IgA, and IgG have been measured in tears by the ELISA (enzyme-linked immunosorbent assay) technique. Tears were collected on weighed filter paper discs, after which they were eluted into buffer and transported frozen to a remote laboratory for assay. Patients with sicca, questionably dry eyes and ocular pemphigoid were sampled, as were 54 normal volunteers. Tear protein profiles were established which were unique for each condition and clearly differed from the normal controls. The assay developed is considered suitable for other proteins such as IgE, and could also be used for monitoring the effects of drugs on the lacrimal gland.