Soluble -selectin and interleukin-8 in otitis media with effusion

Objective: adhesion of leukocytes to vascular endothelium and their invasion into local tissues are important steps in inflammation. -selectin plays a crucial role in leukocyte rolling and adhesion on endothelial cell surface. Interleukin-8 (IL-8) is a potent chemotactic substance toward neutrophils and lymphocytes-T and mediate their migration to local inflammation. The levels of soluble -selectin (s -selectin) and IL-8 were measured in middle ear effusions (MEE) from children with otitis media (OM) to estimate their role in pathogenesis of inflammation in middle ear. Methods: MEE were collected from 113 ears of 62 children during routine myringotomy. The entire specimen was diluted with phosphate-buffered saline (PBS) to 2 ml and centrifugated at 1500 rpm for 15 min to separate cellular components. Supernatants of MEE were stored frozen at −20°C for s -selectin and at −80°C for IL-8 assessment. The concentration of s -selectin and IL-8 were estimated with ELISA and compared with total protein concentration measured by Bradford assay. Results: MEEs from children with chronic mucous otitis media contained significantly higher mean concentrations of IL-8 559.4 pg/mg total protein (TP) (±535.6) in comparison with normal serum 17.79 pg/mg TP (±10.9), serous OM 40.3 pg/mg TP (±28.1) and purulent OM 104.4 pg/mg TP (±128.6). High concentration of IL-8 was found in MEE from the children with early recurrence of OMS. The levels of s -selectin were higher in purulent effusions 77.2 ng/mg TP (±67.4) than those of chronic mucoid 27.6 ng/mg TP (±36.7) and serous OM 26.3 ng/mg TP (±27.1). Conclusion: the results support a hypothesis that IL-8 can be responsible for prolongation of inflammatory process in middle ear, therefore long-term treatment and observation of children with the high levels of IL-8 in MEE may be necessary. Elevated level of s -selectin in acute OM suggests the involvement of -selectin in the acute phase of OM.