Clinical approaches for understanding the expression levels of pattern recognition receptors in otitis media with effusion
OBJECTIVES: Bacterial infections in the normally sterile environment of the middle ear cavity usually trigger host immune response, whereby the innate immune system plays a dominant role as the host’s first line of defense. In this study we evaluated the expression levels of Toll-like receptors (TLRs) -2, -4, -5, -9, and nucleotidebinding oligomerization domain-containing proteins (NODs) -1 and -2, all of which are related to bacterial infection in pediatric patients with otitis media with effusion (OME). METHODS: The study sample consisted of 46 pediatric patients with OME, all of whom had ventilation tubes inserted. The expression levels of TLR-2, -4, -5, -9, NOD-1 and -2 mRNA in middle ear effusion were assessed by polymerase chain reaction. RESULTS: All effusion fluid samples collected from patients with OME showed expression of TLR-2, -4, -5, -9, NOD-1, and -2 mRNA. However, we found no correlations among expression levels of pattern recognition receptors (PRRs) in relation to characteristics of exudates, presence of bacteria, or frequencies of ventilation tube insertion (p>0.05). CONCLUSION: Our findings suggest that exudates of OME patients show PRR expressions that are related to the innate immune response regardless of the characteristics of effusion fluid, presence of bacteria in exudates, or frequency of ventilation tube insertion.