The changes of MRSA infections in chronic suppurative otitis media.

OBJECTIVES: To investigate the epidemiologic and microbiological characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) and hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) infections in the otorrhea of chronic suppurative otitis media (COM) patients. DESIGN: Retrospective study of patients with newly identified MRSA infections from January 1998 through December 2006. A total of 2773 patients with a diagnosis of COM were included in this study. An antibiotic sensitivity test was performed for each isolate. RESULTS: The prevalence of MRSA in COM was 4.9 percent (137 of 2773 patients). The proportion of CA-MRSA rose from 0.7 percent in 1998 to 11.4 percent in 2006. However, the proportion of HA-MRSA did not change significantly, from 0.7 percent in 1999 to 1.3 percent in 2006. All of the CA-MRSA strains identified in our study were susceptible to trimethoprim/sulfamethoxazole (TMP/SMX). Rifampin susceptibility was also noted in 90 percent of the cases. CONCLUSIONS: CA-MRSA infections have risen dramatically in the past decade. CA-MRSA and HA-MRSA in COM differed in both clinical and microbiological aspects.

Expression of oncostatin M in chronic obstructive sialadenitis of the submandibular gland.

OBJECTIVES: We investigated the expression of oncostatin M messenger RNA (mRNA) and protein in normal submandibular glands and those with chronic obstructive sialadenitis and localized the expression of oncostatin M protein. METHODS: Submandibular glands from 10 patients with chronic obstructive sialadenitis as a study group and 10 normal submandibular glands as a control group were examined. Oncostatin M mRNA extracted from submandibular gland was used for reverse transcription-polymerase chain reaction and analyzed semiquantitatively. The difference in expression level of oncostatin M protein between the 2 groups was analyzed through Western blot analysis, and oncostatin M protein was localized immunohistochemically. RESULTS: The expression levels of oncostatin M mRNA and protein were significantly increased in the study group. The protein was predominantly localized in ductal epithelia and infiltrating inflammatory cells and was more strongly expressed in the study group also. CONCLUSIONS: Oncostatin M is expressed in both chronic obstructive sialadenitis and normal submandibular gland, and is up-regulated in chronic obstructive sialadenitis. These results suggest that oncostatin M is involved in the pathologic process of chronic obstructive sialadenitis. However, the physiologic role in normal glands, as well as a possible role in the development of chronic obstructive sialadenitis, remains to be elucidated.

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.

Expression of neutrophil gelatinase-associated lipocalin in human salivary glands.

OBJECTIVES: We performed an observational study of RNA and protein expression in human tissue to examine the distribution of neutrophil gelatinase-associated lipocalin (NGAL) in normal and chronic inflammatory salivary tissues, and to investigate the expression level of NGAL in inflammatory conditions of salivary glands. METHODS: Normal salivary gland tissues and tissue samples of salivary glands with chronic sialadenitis were obtained. Expression of NGAL was investigated by reverse transcriptase-polymerase chain reaction, and semiquantitative analysis of these results was also performed. The differential localization and amount of immunoreactivity to NGAL protein was evaluated by immunohistochemistry and Western blot analysis in normal salivary gland tissues and salivary glands with chronic sialadenitis. RESULTS: NGAL messenger RNA transcripts were detected in the tissues from the salivary glands with chronic sialadenitis, but only a small amount was detected in the tissues from the normal salivary glands. A weak expression of NGAL protein was occasionally seen in a few ductal epithelial cells of normal salivary gland tissue. However, in tissue samples from glands with chronic sialadenitis, the NGAL protein was expressed strongly in ductal epithelial cells and infiltrating inflammatory cells. CONCLUSIONS: These results imply that NGAL is associated with the regulation of inflammation in salivary glands.

Up-regulation of protease-activated receptor 2 in allergic rhinitis.

OBJECTIVES: We compared the patterns of PAR-2 messenger RNA (mRNA) and protein expression in the nasal mucosa of subjects with and without allergic rhinitis. METHODS: Biopsy specimens were obtained from 10 patients with allergic rhinitis and 10 normal controls. RNA was extracted from the nasal mucosa, and semiquantitative reverse transcription-polymerase chain reaction was performed for PAR-2. Tissue sections were immunostained for PAR-2 by use of specific antibody. RESULTS: The expression levels of PAR-2 mRNA in allergic rhinitis nasal mucosa were significantly up-regulated as compared with those in normal nasal mucosa. PAR-2 immunoreactivity was observed in the epithelium and submucosal glands in both normal controls and subjects with allergic rhinitis. Stronger immunoreactivity for PAR-2 was observed in allergic rhinitis nasal mucosa as compared with normal nasal mucosa. CONCLUSIONS: These results suggest that PAR-2 may be involved in allergic nasal inflammation.

Expressions of cyclooxygenase 1 and 2 in endotoxin-induced otitis media with effusion in the rat.

OBJECTIVE: Recently, a selective COX-2 inhibitor was developed and used for reducing the levels of inflammation-inducing prostaglandin (PG) whilst not inhibiting the release of protective PG by COX-1. COX-1 may be the critical isoform required for the production of PG with a homeostatic function, whereas COX-2 may be the main contributor to PG production in inflammation. The purpose of this study was to investigate COX-1 and 2 expressions in experimental endotoxin-induced OME in rats and to quantify their temporal expressions. METHODS: In a rat model, lipopolysaccharides (LPS) were inoculated into the middle ear cavity. Middle ear mucosa and temporal bone were samples at 0, 1, 3, 6, and 12h, and on days 1, 3 and 7 after instilling either LPS or sterile PBS. RT-PCR, Western blotting and immunohistochemical staining were performed to determine the expressions of COX-1 and COX-2. RESULTS: COX-1 mRNA and protein were detected in normal middle ear mucosa but their levels did not change after endotoxin instillation. However, COX-2 was not identified in normal middle ear mucosa, but COX-2 mRNA was maximally increased at 6h after endotoxin instillation and COX-2 protein was maximally increased at 12h. COX-2 expression, by immunohistochemical staining, was identified only at 12h after endotoxin injection. CONCLUSIONS: In this study, the basal expressions of COX-1 and COX-2 mRNA and protein in middle ear mucosa, as well as their regulations by endotoxin were investigated. COX-1 was not induced in middle ear mucosa by endotoxin whereas COX-2 was induced within 12h of stimulation. Our findings indicate that COX-2 inhibitor administration for the relief of inflammation should be considered within 12h of the initiation of an inflammatory process. These findings may provide an understanding of the mechanisms regulating PG formation in infection of the middle ear cavity.

Up-regulation of peroxidase proliferator-activated receptor gamma in cholesteatoma.

OBJECTIVE: To evaluate the localization and expression of peroxidase proliferator-activated receptor (PPAR)gamma in cholesteatoma epithelium. STUDY DESIGN: Experimental study. METHODS: Reverse-transcription polymerase chain reaction was performed on cholesteatoma tissues from 10 adult patients undergoing tympanomastoid surgery for middle ear cholesteatoma and on 10 samples of normal external auditory canal skin tissue. The expression levels of PPARgamma to glyceraldehyde-3-phosphate dehydrogenase transcripts were semiquantified by densitometry. We also characterized the cellular localization of the PPARgamma protein immunohistochemically. Ki-67 was also localized to compare the proliferative activity of cells in cholesteatoma epithelium and in normal external auditory canal skin. RESULTS: PPARgamma mRNA and protein were detected in normal external auditory canal skin and in cholesteatoma epithelium. The expression level of PPARgamma mRNA in cholesteatoma was significantly increased compared with that in normal external auditory canal skin. PPARgamma protein was expressed in cells mainly in the granular and prickle cell layers. However, the intensity of its expression was generally decreased in the parabasal layer of the cholesteatoma epithelium. Ki-67 was expressed in the nuclei of cells in the basal and parabasal layers, and a greater number of cells were Ki-67 immunopositive in cholesteatoma epithelium. CONCLUSION: PPARgamma is up-regulated in the cholesteatoma epithelium compared with normal external auditory canal skin. These results suggest that PPARgamma may play an important role in the pathogenesis of cholesteatoma.

Upregulation of surfactant protein A in chronic rhinosinusitis.

OBJECTIVES: Surfactant protein A (SP-A) is protein that appears to play an important role in mammalian first-line host defense. However, the presence of SP-A in the human paranasal sinus mucosa is not well known. The purpose of this study was to investigate the expression of SP-A protein in human paranasal sinus mucosa and to compare the expression of SP-A mRNA between normal paranasal sinus mucosa and paranasal sinus mucosa with chronic rhinosinusitis. METHODS: Paranasal sinus mucosa samples from 10 patients who underwent surgery for chronic rhinosinusitis without polyps and 10 normal control subjects were used. Reverse transcriptase polymerase chain reaction was done to detect SP-A mRNA. The expression level of SP-A transcripts was semiquantified with desitometry. Cellular localization of SP-A was sought by using immunohistochemistry. RESULTS: SP-A mRNA and protein were expressed in the human paranasal sinus mucosa. SP-A/GAPDH mRNA ratio in the paranasal sinus mucosa with chronic rhinosinusitis was greater compared with that in normal paranasal sinus mucosa (P<.05). Immunohistochemical staining revealed SP-A immunoreactivity in the epithelial cells and submucosal glands of paranasal sinus mucosa in both control subjects and chronic sinusitis patients. Stronger immunoreactivity was observed in chronic rhinosinusitis mucosa as compared with normal paranasal sinus mucosa. CONCLUSION: SP-A mRNA and protein are present in both normal and diseased human paranasal sinus mucosa. These results may provide potential targets for novel therapy of chronic rhinosinusitis.

Treatment of ranula in pediatric patients with intralesional injection of OK-432.

OBJECTIVE: To assess the efficacy of treatment of a ranula in children by intralesional injection of OK-432. STUDY DESIGN: Retrospective analysis of 13 cases. METHODS: Review of medical records of pediatric patients with ranula treated by OK-432 sclerotherapy from 2002 through 2005. RESULTS: Among 13 cases, 9 were completely regressed by injection therapy alone. Three cases were incompletely regressed. One case was cured by surgical excision. The follow-up duration was 6 to 46 (mean 24.3) months. Adverse effects of OK-432 injection were tolerable, and no complication was observed. CONCLUSIONS: On the basis of our experience, sclerotherapy with OK-432 was a safe and effective primary treatment for a ranula in children. Further study will be needed to conclude its long-term effectiveness.

Efficacy of sucralfate in the postoperative management of uvulopalatopharyngoplasty: a double-blind, randomized, controlled study.

OBJECTIVE: To evaluate the effectiveness of sucralfate in influencing throat pain, otalgia, analgesic requirement, bleeding, mucosal recovery, and incidence of postoperative bleeding in patients undergoing uvulopalatopharyngoplasty. DESIGN: A prospective double-blind randomized study. SETTING: University-affiliated tertiary referral hospital. PARTICIPANTS: Eighty adult patients with obstructive sleep apnea syndrome requiring uvulopalatopharyngoplasty were recruited and randomly allocated into either a sucralfate treatment group or a control group. INTERVENTIONS: All patients underwent uvulopalatopharyngoplasty. Patients enrolled in the sucralfate group (n=40) were instructed to gargle the sucralfate suspension and then to swallow. Patients enrolled in the control group (n=40) were instructed to gargle placebo suspension at the same doses and schedule. MAIN OUTCOME MEASURES: Postoperative throat pain, otalgia, amount of analgesic required, degree of strength (defined as patients' general well-being and return to regular daily activities), percentage of mucosal covering, and postoperative bleeding. RESULTS: Throat pain and otalgia occurred significantly less often in sucralfate group, with less analgesic requirement and with rapid mucosal healing and early return to regular daily activities. There was no significant difference in episodes of postoperative bleeding between the 2 groups (P=.37). CONCLUSIONS: Although sucralfate therapy may not provide complete analgesia after uvulopalatopharyngoplasty, it may reduce the amount of analgesic required, thus preventing dose-related adverse effects from the analgesic agent. It can also significantly reduce the total number of days needed to return to normal daily activities (P=.41).

Up-regulation of chemokine ligand 20 in chronic rhinosinusitis.

OBJECTIVES: To investigate the up-regulation of chemokine ligand 20 (CCL20) in chronic rhinosinusitis mucosa and to localize the distribution of CCL20 in the human paranasal sinus mucosa. DESIGN: Prospective study. SETTING: Tertiary academic institution. PATIENTS: Ten patients who underwent functional endoscopic sinus surgery for chronic rhinosinusitis without nasal polyps and 10 normal control subjects. INTERVENTIONS: Messenger RNA was extracted from the sinus mucosa, and semiquantitative reverse transcriptase-polymerase chain reaction was performed. Immunohistochemical staining was used to localize the CCL20 protein. RESULTS: The expression levels of CCL20 messenger RNA level in chronic rhinosinusitis without nasal polyps were significantly increased compared with those in normal sinus mucosa. The expression of CCL20 protein was greater in chronic rhinosinusitis without nasal polyps mucosa and was localized to the epithelial and submucosal glandular cells. CONCLUSION: CCL20 is an inducible product of human paranasal sinus epithelium that may play a role in modulating mucosal immunity of the sinus mucosa.

Up-regulation of peroxisome proliferator-activated receptor gamma in perennial allergic rhinitis.

OBJECTIVES: To investigate the expression of peroxisome proliferator-activated receptor gamma (PPAR-gamma) messenger RNA and protein and to localize the PPAR-gamma protein in the nasal mucosa of patients with allergic rhinitis and control subjects. DESIGN: Prospective study. SETTING: Tertiary academic institution. Patients Twenty patients with perennial allergic rhinitis and 20 matched nonallergic patients. INTERVENTIONS: Inferior turbinate mucosa samples were obtained from 20 patients with perennial allergic rhinitis and 20 matched nonallegic patients. Peroxisome proliferator-activated receptor gamma messenger RNA was extracted from the inferior turbinate mucosae, and then reverse transcription-polymerase chain reaction was performed. Western blot testing was used to analyze differences in PPAR-gamma protein expression levels between patients with allergic rhinitis and normal controls, and the PPAR-gamma protein was localized immunohistochemically. RESULTS: The expression levels of PPAR-gamma messenger RNA and protein in the nasal mucosa was significantly increased in patients with perennial allergic rhinitis compared with controls. Peroxisome proliferator-activated receptor gamma protein was expressed in the epithelium, infiltrating inflammatory cells, and submucosal glands. CONCLUSIONS: Peroxisome proliferator-activated receptor gamma is expressed in the human nasal mucosa and is up-regulated in perennial allergic rhinitis. These results suggest a possible contribution for PPAR-gamma in chronic inflammation of the nasal mucosa in perennial allergic rhinitis.

Expression of cathelicidin in recurrent throat infection.

BACKGROUND: Epithelial cells can be called the first line of a defense barrier to microorganisms by the innate immune system. The antimicrobial peptides are the major participants of this system. Cathelicidins are a family of peptides thought to provide an innate defensive barrier against a variety of potential microbial pathogens. OBJECTIVES: To evaluate the expression of the cathelicidin in recurrent throat infection. PATIENTS AND METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemical staining were performed for 10 palatine tonsil tissues with hypertrophy and 10 palatine tonsil tissues with recurrent throat infection. RESULTS: Cathelicidin mRNA transcripts were detected in recurrent throat infection. The expression levels of cathelicidin mRNA in recurrent throat infection was significantly higher compared with those in hypertrophic tonsils. Cathelicidin protein was localized on the tonsillar surface epithelium and inflammatory cells in the tonsillar crypt of recurrent throat infection patients. CONCLUSION: These results suggest that cathelicidin is one of antimicrobial peptides in the human palatine tonsils, and that cathelicidin may also play an important role in innate host defense of human tonsils.

Interleukin-18/-607 gene polymorphism in allergic rhinitis.

OBJECTIVES: Allergic rhinitis is a chronic inflammatory disease with a genetic background, and IL-18 (formerly IFN-gamma-inducing factor) is a well-known pro-inflammatory cytokine. The aim of this study was to investigate whether the IL-18/-607 promoter polymorphisms were associated with allergic rhinitis in the Korean population. STUDY DESIGN: Prospective study. METHODS: Deoxyribonucleic acid was obtained from the blood samples of 160 Korean children with allergic rhinitis and from 166 healthy controls. The IL-18/-607 polymorphism was analyzed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: The frequency of the AC genotype of the IL-18/-607 gene polymorphism was significantly greater in allergic rhinitis patients than in controls (P<0.05). CONCLUSIONS: The A allele in the IL-18/-607 gene promoter region may be involved in the development of allergic rhinitis in the Korean population.

Polymorphism of the CD14 gene in perennial allergic rhinitis.

OBJECTIVES: Allergic diseases have strong genetic backgrounds. Recently, a C-T polymorphism in the promoter region of CD14 has been associated with phenotypes of atopy in some populations. The aim of this study was to investigate the association of CD14/-159 polymorphism with total serum IgE levels and number of positive skin prick tests in Korean population with perennial allergic rhinitis. STUDY DESIGN: Prospective study. METHODS: Deoxyribonucleic acid obtained from 164 children with perennial allergic rhinitis and 160 healthy controls were typed for the promoter polymorphism of CD14 gene at position -159 by restriction fragment length polymorphism analysis. Genotype frequencies, total serum IgE levels, and the number of positive skin tests for each genotype were compared. RESULTS: There were no significant differences in the CD14/-159 genotype frequencies between the allergic rhinitis group and the control group. In the skin prick test-positive population, the CC homozygotes were associated with higher serum total IgE levels and greater number of positive skin tests compared with subjects with CT and TT alleles (P<0.05). CONCLUSIONS: The results from the present study suggest that CD14/-159 polymorphism may play a role in the development of perennial allergic rhinitis in Korean children.

Overexpression of placenta growth factor in human middle ear cholesteatoma.

CONCLUSIONS: The expression and localization of placenta growth factor (PlGF) within cholesteatoma were defined. The authors propose that PlGF is an angiogenic growth factor in cholesteatoma, and participates in the neoangiogenesis of cholesteatoma. OBJECTIVES: Middle ear cholesteatoma is characterized by the presence of a keratinizing squamous epithelium with hyperproliferative features. Such growth can only be supported by abundant blood vessels. Because proliferating tissues require an enhanced blood supply, angiogenesis appears to be a prerequisite for the expansion of cholesteatoma. This study aimed to analyze the presence of PlGF as an angiogenic growth factor in human cholesteatoma. MATERIALS AND METHODS: Tissue samples from human cholesteatoma and normal auditory meatal skin were obtained from patients during surgery for cholesteatoma of the middle ear. PlGF mRNA expression was quantified by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). PlGF was localized by immunohistochemical staining. Western blotting was used for detection of PlGF protein. RESULTS: Expression of PlGF mRNA was significantly elevated in the epithelium of cholesteatoma compared with normal auditory meatal skin. PlGF was detected on cholesteatoma by Western blotting. PlGF was detected in the suprabasal layer of cholesteatoma using immunohistochemical study, but was not detected in normal auditory meatal skin.

Upregulation of oncostatin m in allergic rhinitis.

OBJECTIVES: Oncostatin M is a multifunctional cytokine belonging to the interleukin-6 family of cytokines. It has been implicated as an important modulator of lower airway remodeling in the setting of asthma. However, there have been few studies regarding a similar role for the upper airway epithelium in the setting of allergic rhinitis. This study was undertaken to investigate the expression of oncostatin M mRNA and protein in normal and allergic rhinitis nasal mucosa and to localize the expression of the oncostatin M protein in allergic rhinitis. MATERIALS AND METHODS: Inferior turbinate mucosa samples from 20 patients with perennial allergic rhinitis and 20 matched normal control subjects were obtained. Oncostatin M mRNA was extracted from the inferior turbinate mucosae, then reverse transcriptase-polymerase chain reaction was performed and analyzed semiquantitatively. Differences in expression levels of oncostatin M protein between samples from allergic rhinitis patients and normal control subjects were analyzed through Western blot, and oncostatin M protein was localized immunohistochemically. RESULTS: The expression levels of oncostatin M mRNA and protein were significantly upregulated in patients with allergic rhinitis mucosa. Oncostatin M protein was predominantly localized in the surface epithelium, infiltrating inflammatory cells, vascular endothelium, and submucosal glands and was more strongly expressed in the nasal mucosa of patients with allergic rhinitis than in normal control subjects. CONCLUSIONS: Oncostatin M is expressed in the human nasal mucosa and is upregulated in the setting of allergic nasal inflammation. These results suggest a possible contribution of oncostatin M in the remodeling of the nasal mucosa in allergic rhinitis.

Up-regulation of surfactant protein A in chronic sialadenitis.

OBJECTIVES: Salivary secretions play a critical role in maintaining the health of the oral cavity, which is the first gate of entry to the airways and thus is exposed to a variety of environmental insults. Surfactant protein A (SP-A) is a member of the collectin family and plays an important role in first-line airway defense. The objectives of this study were to examine the expression of SP-A messenger RNA and protein in human salivary glands and to investigate its up-regulation during inflammatory conditions. DESIGN: Reverse transcription-polymerase chain reaction was performed on salivary gland tissues from patients and a control group. The expression levels of SP-A to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) transcripts were semiquantified by densitometry. We also characterized the cellular localizations of SP-A protein immunohistochemically. SETTING: Tertiary academic institution. PATIENTS: Ten patients with chronic sialadenitis and 10 patients with healthy salivary glands. RESULTS: Surfactant protein A messenger RNA and protein were detected in glands of patients who were healthy and in those with chronic sialadenitis. The expression levels of SP-A messenger RNA in the salivary glands of patients with chronic sialadenitis was significantly increased compared with those in healthy salivary glands. Immunohistochemical staining revealed SP-A immunoreactivity in the ductal epithelia of healthy salivary glands and in the salivary glands of those with chronic sialadenitis, and stronger immunoreactivity was observed in those with chronic sialadenitis tissues. CONCLUSIONS: Surfactant protein A is present in the salivary gland epithelium and is up-regulated in individuals with chronic sialadenitis. These results suggest that salivary gland SP-A may play an important role in the innate host defense of human salivary glands.

Monostotic fibrous dysplasia of temporal bone: report of two cases and review of its characteristics.

Fibrous dysplasia is a bone disorder of unknown origin characterized by slow, progressive replacement of bone by abnormal proliferative isomorphic fibrous tissue. The disease was first described by McCune and Bruch in 1937. Craniofacial involvement is found in only 10% of cases of the monostotic variety, while temporal bone involvement is rare. We report herein two cases of monostotic fibrous dysplasia involving temporal bone and briefly review the clinical implications and management of the disease.

Expression of a cathelicidin antimicrobial peptide is augmented in cholesteatoma.

OBJECTIVES/HYPOTHESIS: Antimicrobial peptides are active defense components of innate immunity. Their importance was confirmed at epithelial surfaces as immediate barrier effectors in preventing infection. Cathelicidins are peptide antibiotics that are receiving increasing attention. Several studies have shown that overexpression of cathelicidin results in augmented protection against bacterial infection and prevention of local infection and systemic invasion of microbes. The goal of the study was to investigate whether cathelicidin is upregulated in cholesteatoma epithelium compared with normal skin. STUDY DESIGN: Twenty patients from a prospective study of cholesteatoma tissues and normal skins were enrolled in the study. The specimens were divided into two portions. One portion was used for subsequent RNA studies; the other was used for immunohistochemical staining. METHODS: Reverse transcriptase-polymerase chain reaction was used to assess the expression levels of cathelicidin messenger RNA (mRNA) both in cholesteatoma and in normal skin. Presumptive concentration of cathelicidin mRNA and beta2-microglobulin mRNA was evaluated. Ratio of beta2-microglobulin to cathelicidin was analyzed in each group. The expressions of cathelicidin in cholesteatoma and normal skin epithelium were investigated by an immunohistochemical technique. RESULTS: Cathelicidin mRNA in cholesteatoma epithelium was increased 5.5-fold compared with normal skin of the ear canal. In cholesteatoma epithelium, cathelicidin was located in all the layers, but in the normal skin it was expressed only in the granular and prickle cell layers. CONCLUSIONS: Cathelicidin is augmented in cholesteatoma epithelium, and the data in the present study are in agreement with the hypothesis that cathelicidin is likely to act as a key component in the first line of defense at the surface epithelium.