Age-dependent changes in pattern recognition receptor and cytokine mRNA expression in children with otitis media with effusion

Objective: To investigate age-dependent changes in expression of pattern recognition receptors (PRRs) and cytokines in pediatric OME.

Materials and methods: Ninety five pediatric patients with OME were divided into 4 age groups: 0-2, 2-4, 4-7, and over 7 years. The presence of bacteria, and the levels of expression of mRNAs encoding Toll-like receptor (TLRs), NOD like receptors (NLRs) and cytokines in middle ear fluid were assessed, as were their correlations with age, gender, presence of bacteria and accompanying disease.

Results: Bacteria were detected in 32.6% of patients. The levels of expression of PRR and cytokine mRNAs tended to be lower in children aged 2-4 and 4-7 years. The levels of expression of TLR-2, TLR-9, NOD-1, NOD-2, IL-1, IL-6, and TNF-α mRNAs in effusion fluid were significantly lower in these two groups than in children aged 0-2 and over 7 years (p<0.05 each). The levels of expression of TLR-4, TLR-5, TLR-9, and NOD-1 mRNAs were significantly lower in culture positive than in culture negative patients (p<0.05 each). However, the expression levels of PRR and cytokine mRNAs were unrelated to gender and accompanying disease (p>0.05 each).

Conclusions: The levels of expression of PRR and cytokine mRNAs differed by age in children with OME.