Expression of antimicrobial peptides in recurrent adenotonsillitis

Abstract

Background: Recurrent acute tonsillitis is one of the most frequent otorhinolaryngology clinic referrals, yet its pathogenesis remains poorly understood. Antimicrobial cationic peptides are components of the innate system. They are generally small, highly positively charged peptides with broad spectrum antimicrobial activity which function as the body's "natural antibiotics". Our aim is to investigate the role of antimicrobial cationic peptides in the susceptibility of patients to recurrent acute tonsillitis. Materials and methods: The study is done with 100 children who had a history of recurrent adenotonsillitis as subject group and 100 children with adenotonsillar hypertrophy as control group. Tonsillar and adenoid tissues are dissected into parts as deep and surface epithelium and investigated semiquantitatively with immunohistochemistry. Human beta defensin (hBD) 1-3 and cathelecidin (LL-37) levels are compared with microscopically. Results: Immunohistochemistry revealed a strong expression of hBD-1, hBD-2 and hBD-3 in tonsillar tissue. Quantification of hBD-1, hBD-2 and hBD-3 expressions are shown more in tonsillar tissue than in adenoids. LL-37 is one of the antimicrobial peptides found in human tonsillar tissue and adenoids, that participates in the innate immune system of these tissues. Statistically, hBD-1, hBD-3 and LL-37 expressions were different in recurrent tonsillitis tissue than control (p < 0.05). Moreover hBD-2 expression was different in adenoid tissue than control (p < 0.05). Conclusion: Antimicrobial peptides have key role in adenotonsillar infections and this defense mechanism increases susceptibility to recurrent infections in upper respiratory tract.