Immunologic and cytologic studies in otitis media with effusion.

Detection of immune complexes (ICs) of IgG, IgM, or IgA isotypes in middle ear effusions (MEEs) by the solid-phase anti-C3 ELISA and cytologic analyses of MEEs were done in 245 patients with otitis media with effusion (OME). In 320 ears, the clinical classification was acute, 10.3%; subacute, 16.6%; chronic, 73.1%. In the cytologic analyses, the predominant types in each clinical stage were as follows: neutrophil dominant (N) type (63%) in acute cases; neutrophils and lymphocytic (Mixed) type (37%) in subacute cases; and cellular remnant (CR) type (37.8%) in chronic cases. In all the clinical stages IgG-ICs were positive in over 50% of cases and acute cases showed the highest positive rate (64%). IgA)ICs were found in all clinical stages and the highest positive rate was found in subacute cases (67%). In chronic cases, MEEs of N type showed the highest IgG-ICs level and positive rate (75%). These results suggested that immune complexes formed in the middle ear cavity might play an important role in the prolonged inflammatory process of OME through the complement activation following chemotaxis of neutrophils.