Higher Serum Levels of Interleukin 10 Occur at Onset of Acute Otitis Media Caused by Streptococcus Pneumoniae Compared to Haemophilus Influenzae and Moraxella Catarrhalis

Objectives/Hypothesis Acute otitis media ( AOM ) involves an inflammatory response to microbes in the middle ear that facilitates clearance of otopathogens. Clinically , Streptococcus pneumoniae (Spn) infections of the respiratory tract are characterized by greater inflammatory responses than nontypeable Haemophilus influenzae ( NTHi ) and Moraxella catarrhalis (Mcat) . Interleukin 10 ( IL ‐10) plays an important role in down‐regulating the inflammatory response. We compared serum IL ‐10 levels in children before onset, at onset, and after recovery from AOM caused by Spn, NTHi , and Mcat . We sought to determine if IL ‐10 could serve as a biomarker to distinguish AOM caused by Spn versus NTHi and Mcat . Study Design Prospective, longitudinal study in a primary care pediatric practice in Rochester, NY. Methods Participants were 54 children, 6 to 30 months of age. Outcomes measured were serum IL‐10 levels when healthy, at onset of AOM, and after recovery from AOM. Results Serum IL‐10 was elevated when children developed AOM ( P =0.013) due to infections caused by Spn ( P =0.011) but not AOM caused by NTHi or Mcat . Middle ear fluid levels of IL‐10 mirrored those seen in serum but were 10‐fold higher ( P =0.02). Other effector cytokines in serum: IL‐4, IFN‐γ, and TNF‐alpha, did not show the same increases as IL‐10 at onset of AOM. Conclusion Our study indicates that AOM caused by Spn elicits a significantly higher IL‐10 response compared to NTHi and Mcat and may prove to be a biomarker of AOM infections by Spn . Level of Evidence 4.