Objective: To determine whether organized mucosa-associated lymphoid tissue (MALT) is a normal component of the human efferent tear ducts or is acquired in reaction to chronic inflammation.
Design: Nonrandomized comparative (cadaver controlled) study with histopathologic correlations.
Materials: Tissue specimens from nasolacrimal ducts of 38 patients undergoing endonasal dacryocystorhinostomy in postinflammatory dacryostenosis with signs of chronic inflammation were analyzed using histologic examination and immunohistochemical studies. Only tissue specimens revealing proliferative sclerotic forms of chronic fibrosis were chosen for the study. Eighty specimens from the lacrimal systems of body donors served as controls.
Testing: Tissue specimens from each lacrimal system were prepared and processed with paraffin, sectioned, stained using different histologic methods with an array of specific antibodies, and examined by light microscopy.
Main outcome parameters: The distribution of intraepithelial and subepithelial defense cells was analyzed to identify plasma cells, secretory immunoglobulins, lymphocytes, dendritic cells, and organized mucosa-associated lymphoid tissue.
Results: The presence of secretory immunoglobulin A was demonstrated in subepithelial plasma cells and in the cytoplasm of apical epithelial cells in both chronically inflamed and healthy lacrimal systems. In more than one third of cases from body donors, but in only a few biopsy specimens from patients, organized lymphoid tissue was found with the cytomorphologic and immunophenotypical features of MALT. All other cases showed a diffuse infiltrate of defense cells within the lamina propria.
Conclusions: The development of tear duct-associated lymphoid tissue (TALT) is a common feature that is often found in symptomatically normal nasolacrimal ducts. Because TALT seems to be lost associated with the scarring of symptomatic dacryostenosis, it is unlikely that the presence per se of TALT leads to scarring. Future studies are needed to explain the development of TALT.