Serum antibodies specific to CD outer membrane protein of Moraxella catarrhalis, P6 outer membrane protein of non-typeable Haemophilus influenzae and capsular polysaccharides of Streptococcus pneumoniae in children with otitis media with effusion

We measured the levels of serum IgG antibodies to CD outer membrane protein of Moraxella catarrhalis, P6 outer membrane protein of non-typeable Haemophilus influenzae and capsular polysaccharides of Streptococcus pneumoniae in 168 children with otitis media with effusion (OME) who were followed prospectively, using ELISA. Serum IgG antibodies to CD, P6 and pneumococcal capsular polysaccharides were detected in all samples. The anti- pneumococcal polysaccharides antibody level was highest, followed by the anti-P6 antibody level and anti-CD antibody was lowest (median:interquartile ranges were 45.9:19.1 - 100 μg/ml, 15.6:9.70-23.2 μg/ml and 1.06:0.73-1.87 μg/ml, respectively). In children aged 0-6 years, there were positive correlations among the antibody levels (anti-CD vs anti-P6, r= 0.325, p <0.001; anti-CD vs anti-polysaccharide, r= 0.397, p < 0.0001; anti-P6 vs anti-polysaccharide, r = 0.175, p =0.057). However, no relationship was seen in children aged 7-15 years. Children were classified according to severity of OME during the 1-year follow-up. In children aged 0-6 years, the severity of OME correlated inversely with the levels of anti-CD antibody (r = -0.23, p = 0.012), of anti-P6 antibody r = -0.292, p = 0.0015), and of anti- pneumococcal polysaccharides antibody (r = -0.25, p= 0.0064). However, no correlation was found between antibody levels and severity of OME in children aged 7-15 years. These data suggest that persistence and/or recurrence of OME may be due to an insufficient serum antibody response to middle ear pathogens in young children.