Interleukin-8 and chemotactic activity of middle ear effusions

The importance of interleukin (IL)-8 in the chemotactic activity of middle ear effusions (MEEs) was evaluated. There was a significantly higher IL-8 concentration in MEEs of children with acute otitis media (AOM) (n = 17; 136 ng/mL) than in children with otitis media with effusion (OME) (n = 28; 65 ng/mL). The IL-8 concentration in MEEs with bacteria (149 ng/mL) was significantly higher than in MEEs without bacteria (66 ng/mL). MEEs from children with AOM and OME had equally higher chemotactic activity than the diluent alone (23.3% and 24.8% vs. 9.2%). The chemotactic activity was not altered by the presence of bacteria nor did it correlate with IL-8 concentration. Fractionation of MEEs by gel chromatography demonstrated that the main chemotactic activity could clearly be separated from the IL-8 activity, thus excluding IL-8 as a main chemotactic component in MEEs.