COMPOSITIONAL DIFFERENCES BETWEEN BILATERAL MIDDLE-EAR EFFUSIONS IN OTITIS-MEDIA WITH EFFUSION - EVIDENCE FOR A DIFFERENT ETIOLOGY

The aim of this study was to clarify the site of primary pathology in otitis media with effusion. Effusions were collected from 64 children with bilateral effusions at the time of myringotomy. The rheological p roperties and biochemical compositions of effusions were measured for 23 pairs of effusions, and the levels of the inflammatory mediators TN F alpha, IL-1 beta, and IL-8 were measured in 41 pairs using specific enzyme-linked immunosorbent assays (ELISAs). Measurements from paired ears were compared using analysis of variance (ANOVA) tests and signif icant differences were found for reduced specific viscosity, mucin con tent, protein content, and Levels of IL-8. The results demonstrate tha t the two ears have different immunological processes or rates of proc esses which might explain the significantly different rheological prop erties of effusions. This suggests that each ear undergoes pathologica l changes independently and has implications for using the opposite ea r as a control in clinical trials.