Studies on distribution of α1-antitrypsin, lysozyme, lactoferrin, and mast cell enzymes in diseased middle ear mucosa.

CONCLUSIONS

Antimicrobial agents (AMAs) and mast cells in chronic otitis media (COM) may play a protective role in the pathogenesis of COM. Among them, our results indicated that lysozyme may be the most important parameter of the mucosa infectivity in COM.

OBJECTIVE

AMAs include alpha 1-antitrypsin (α1-AT), lysozyme, and lactoferrin and exhibit innate immune activity that is known to play a critical role in mucosal defenses. In addition, proteases expressed in mast cells contribute to mucosal defenses. The aim of this study was to identify AMAs responsible for COM as well as their association with middle ear mucosal diseases.

METHODS

Middle ear mucosa (MEM) was intraoperatively collected by biopsy from patients, diagnosed as COM without or with cholesteatoma, and immediately processed for immunohistochemical study to evaluate expression of AMAs and mast cell proteases (chymase and tryptase).

RESULTS

The AMAs and mast cell enzymes were observed prominently in the chronic middle ear diseases whereas immunoreactivity of α1-AT and lysozyme was not significantly increased in the COM with cholesteatoma compared with that in COM without cholesteatoma. Lactoferrin was not detected in the diseased MEMs.