Lysozyme distribution in human lacrimal glands and other ocular adnexa

In an immunohistochemical study of the human lacrimal glands and other orbital adnexa, lysozyme was found to be present in the major and accessory lacrimal glands but absent from meibomian glands and conjunctival epithelium. Almost all acinar and tubular cells in major and accessory lacrimal glands contain lysozyme, although occasional cells show diminished staining for lysozyme, probably because of secretion. Only one secretory lacrimal tubuloacinar cell type is demonstrable, although two types previously have been described. Lacrimal duct cells do not contain lysozyme. The findings of this study support the concept that the tubuloacinar cells of the main and accessory lacrimal glands are the sole source of the lysozyme secreted into tears.