['Otitis media with effusion (OME) is a condition that has significant impact on the quality of life of children. Although the etiology is multi-factorial, certain risk factors such as an allergic predisposition, daycare, and cigarette smoke exposure contribute to its pathogenesis.', '(1) To determine whether there is a tendency for children with chronic or recurrent OME (cases) to have higher serum levels of the T-helper 2 cell (Th-2) allergenic-type cytokines, interleukin-4 (IL-4), and IL-5, or the T-helper 1(Th-1) infectious-type cytokines, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha), compared to children without a history of recurrent OME (controls) and (2) to determine any possible correlations between the cytokine levels and risk factors associated with OME.', 'We analyzed serum levels of these four cytokines by enzyme-linked immunosorbent assays of 19 cases and 17 controls.', 'Cases, independent of age, had increased levels of serum IL-5 compared to controls (p=0.014). While a significant difference in serum IL-4 levels did not exist between cases and controls, children exposed to cigarette smoke had significantly higher levels of serum IL-4 (p=0.003). While serum levels of IFN-gamma were statistically significantly higher in cases than controls with univariate analysis (p=0.011), when controlling for age and smoke exposure with multivariate analyses, the difference did not reach significance (p=0.086).'] Do presence of otitis media with effusion and its risk factors affect serum cytokine profile in children?