Toll-like receptor activation by sino-nasal mucus in chronic rhinosinusitis

Abstract

Background: The sino-nasal disease chronic rhinosinusitis (CRS) is primarily an inflammatory condition that manifests in several ways. However, the aetiology of this complex disease is poorly understood. The aim of this study was to explore the association between toll-like receptor (TLR) activation, host immune response and sino-nasal mucus in healthy and diseased patients. Methods: The activation of TLR2/1 and TLR4 by sino-nasal mucus from 26 CRS patients and 10 healthy controls was measured. In addition, 7 inflammatory cytokines, bacterial community composition and bacterial abundance within the sino-nasal mucus were measured using molecular and diagnostic tools. Results: TLR activity was observed in 9/36 samples, including 2 healthy controls. There was a strong, positive correlation between members of the Gammaproteobacteria (Haemophilus, Enterobacter, Pseudomonas) and TLR2/1 and TLR4 activity. Bacterial abundance and cytokine (tumour necrosis factor) abundance were also positively correlated with TLR activity. Conclusions: These findings suggest that a small proportion (20-30%) of individuals in each sub-group are more predisposed to TLR activity, which may be related to bacterial composition, diversity and abundance in the sinuses.