Expression of Toll-Like Receptor 2 and Toll-Like Receptor 4 in Cholesteatoma

Byun, Jae Yong; Cha, Chang Il; Yeo, Seung Geun; Lee, Sun Kyu; Cho, Joong Saeng

Abstract

BACKGROUND AND OBJECTIVES: One of the hallmarks of aural cholesteatoma is chronic and recurrent infection. Initiation and perpetuation of the inflammatory response of cholesteatoma may result from an exaggerated host defense reaction of the cholesteatoma epithelium. However, the role of innate immune system in cholesteatoma has not been fully elucidated. Toll-like receptors (TLRs) are a part of the innate immune system involved in the response to microbial pathogen. TLRs appear to respond to pathogens and induce NF-kappaB activation. TLR 2 and TLR 4 seem to be related to the initiation of immune responses against gram negative and positive bacteria. We have investigated the expression of TLR 2, and 4 in the normal external auditory canal skin and cholesteatoma.
SUBJECTS AND METHOD
A real time RT-PCR was performed to determine and quantify the expression of TLR 2 and 4 mRNA. Immunohistochemical staining was performed for 17 cases of cholesteatoma and 8 cases of normal auditory canal skin to demonstrate the distribution of TLR 2 and 4.
RESULTS
All cholestatoma and normal external auditory canal skin expressed both TLR 2 and 4 mRNA. The mRNA of TLR 2 and 4 were expressed significantly higher in cholesteatoma than in the normal external auditory canal skin (p<0.05). Immunohistochemistry using anti-TLR2 and anti-TLR4 antibody revealed the expression of TLR 2 and 4 in the epithelial cells of the cholesteatoma.
CONCLUSION
These findings suggest that distinctive patterns of the innate immune related receptors, TLR 2 and 4 system, constitute a part of the innate immune system in the cholesteatoma.