Bacterial antigens and neutrophil granule proteins in middle ear effusions.

Otitis media with effusion is a significant cause of hearing loss in young children. We hypothesized that persistent bacterial antigens in middle ear effusions (MEEs) might act as chronic inflammatory stimuli causing release of neutrophil proteins. Concentrations of neutrophil lactoferrin and a 37-kd cationic bactericidal protein (CAP 37) were measured in 47 MEEs collected from 27 children at the time of tympanostomy tube placement. Antigens of Streptococcus pneumoniae were detected by latex particle agglutination and those of Haemophilus influenzae by dot-blot assay. Bacterial antigens were detectable in 24 (51%) of MEEs: S pneumoniae in 10 (21%), H influenzae in 12 (26%), and both antigens in 2 (4%). Concentrations of lactoferrin and CAP 37 in H influenzae antigen-positive MEEs were significantly higher than in either S pneumoniae antigen-positive or antigen-negative MEEs. We conclude that H influenzae antigen causes a greater middle-ear inflammatory response, as judged by neutrophil products, than does S pneumoniae antigen.