Dynamics of nasopharyngeal colonisation and correlations with lymphocyte populations in the adenoid & peripheral blood of chronic otitis media-prone children

Aim: Nasopharyngeal cultures of chronic otitis media (COM)-prone and non COM-prone children were correlated with blood and adenoid lymphocyte populations to evaluate microbe-host relationships relating to the pathogenesis of COM. The clinical significance of nasopharyngeal aspirate (NPA) culture as a screening tool for adenoid culture was also assessed. Methodology: Forty children scheduled for adenoidectomy were enrolled into COM-prone or non COM-prone groups (for each, n = 20). Conventional culture was performed for adenoid biopsy and NPA bacteriology. Peripheral blood and adenoid mononuclear cells (PBMC and AdMNC, respectively) were stained with viability stain, monoclonal anti-CD19, anti-CD3, anti-CD4, anti-CD8, anti-CD25 and anti-CD127. Cells were permeabilised, fixed and intracellularly stained with monoclonal anti-FoxP3 and quantified by flow cytometry. Results: Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalisand non-typeable Haemophilus influenzae (NTHi) were positive in 44%, 39%, 22% and 22% of COM-prone children with no significant differences compared to non COM-prone children. S. pneumoniae NPA culture was a significant predictor of S. pneumoniae culture at the adenoid (OR = 39.30, CI = 3.68 – 419.28, p = 0.002). Children with positive otopathogen nasopharyngeal culture had significantly more FoxP3+ CD25hi+ CD127lo+ PBMC (M = 4.4%) compared to otopathogen culture negative children (M = 3.1%, p = 0.005). Conclusion: Otopathogens are positively associated with regulatory T cells, potentially inducing a suppressive effector response to promote colonisation and infection chronicity, thus supporting further investigation of their influence on lymphocyte activity. S. pneumoniae NPA cultures may be of direct clinical benefit to clinicians in making diagnoses and recommendations for prophylactic antibiotic therapies in COM.