Expression of human alpha-defensin 5 (HD5) mRNA in nasal and bronchial epithelial cells.

BACKGROUND/AIMS: Human defensins are antibiotic peptides expressed in myeloid and epithelial cells. Human alpha-defensin 5 (HD5) has been detected in Paneth cell granules in the crypts of Lieberkühn and has recently been identified in the female reproductive tract. The aim of this study was to investigate the presence of HD5 mRNA in nasal and bronchial epithelial cells. METHODS/RESULTS: Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) analysis showed that HD5 mRNA was expressed infrequently and to varying degrees in bronchial and nasal epithelial cells. In situ hybridisation resulted in a positive signal in the epithelial layer of nasal polyps. HD5 mRNA was locally restricted to a specific area of epithelial cells and also occurred in submucosal glands. CONCLUSIONS: HD5 mRNA expression in nasal and bronchial epithelial cells is rare and seemed to be locally induced. The results indicate that HD5 might play a role in innate defence in nasal and bronchial epithelia.