Innate Immunity in the Paranasal Sinuses: A Review of Nasal Host Defenses

Abstract

Background Chronic rhinosinusitis (CRS) is a common inflammatory disorder of the paranasal sinuses. An abnormal host response to common bacterial or fungal pathogens is thought to be an important factor in the disease process. Host sinonasal epithelium plays an important role in initially recognizing the presence of microbes and responding by increasing production of antimicrobial peptides and cytokines, with recruitment of phagocytes and lymphocytes of the adaptive immune system, to eliminate the infection. Recently, the innate immune system and its complex interplay with the adaptive immune system are increasingly being recognized as important in the pathogenesis of chronic inflammatory diseases such as asthma and CRS. Methods Review of recent findings on innate immunity in the pathogenesis of CRS. Results New areas of research into potentially novel therapies for CRS are highlighted in this review, with emphasis on toll-like receptors, antimicrobial peptides (cathelicidins and defensins), and surfactant proteins. Conclusion This review provides an overview of innate immunity in the sinonasal tract and discusses potential use of innate immune peptides as treatments against fungi, biofilms, and superantigens in CRS.