Differential expression of human beta defensin 2 and human beta defensin 3 in human middle ear cholesteatoma

Objectives: The purpose of this study was to investigate the differential expressions of human beta defensin (hBD) 2 and hBD-3 in human middle ear cholesteatoma epithelium. Methods: The expressions of hBD-2 and hBD-3 were analyzed by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical staining. Samples were obtained from 10 patients who underwent middle ear surgery for middle ear cholesteatoma. Results: Real-time RT-PCR and Western blot analysis showed that the messenger RNAs and proteins of hBD-2 and hBD-3 were higher in the cholesteatoma epithelium than in normal external auditory canal skin. In cholesteatoma epithelium, hBD-2 and hBD-3 activities were present in the upper granular layer and in the prickle cell layer, but in the normal skin they were poorly expressed in all layers. Conclusions: Increased expressions of hBD-2 and hBD-3 in cholesteatoma epithelium suggest that cholesteatoma, a chronic inflammatory state of middle ear keratinocytes, may induce an innate immune response. That the induction of hBD-2 was found to be more intense than that of hBD-3 in cholesteatoma epithelium implies that hBD-2 is the major effector in terms of chronic epithelial inflammatory responses.