Alteration of mucin in human conjunctival epithelia in dry eye

The objective of this study was to determine whether alteration in mucins could be detected in patients with dry eye symptoms by using the monoclonal antibody H185, which recognizes carbohydrate epitopes on mucin molecules.

Immunohistochemistry and immunoelectron microscopy was used to examine binding of H185 antibody to conjunctival cells obtained by nitrocellulose filter paper stripping (impression cytology). Two study populations were examined. Study I included 22 patients with dry eye symptoms and 13 normal volunteers. Study II included 16 aqueous-deficient dry eye patients and 14 age-matched control subjects.

Results of the studies demonstrated significant differences in binding patterns of H185 to conjunctival cells in normal eyes compared with those of patients with dry eye symptoms. In normal eyes, the antibody bound to apical cells in a mosaic pattern, with cells exhibiting either light, medium, or intense binding. A predominant pattern in patients with dry eye symptoms was loss of the mosaic pattern with replacement by a "starry sky" pattern in which there was a lack of apical cell binding (hence, dark sky) but increased binding to goblet cells (hence, stars in the sky). The starry sky pattern correlated with rose bengal staining.

From these studies it is concluded that there is an alteration either in mucin distribution or mucin glycosylation on the surfaces of apical conjunctival cells in dry eye and that glycosylation of goblet cell mucins changes with the disease.