IgA in Middle Ear Effusions

Abstract

To investigate the nature of middle ear effusion (MEE), secretory IgA, serum type IgA, and albumin were measured respectively by electrommunodiffusion method in 87 mucoid effusions and 54 serous effusions. Antibody activities of secretory IgA against the M antigen of streptococcus pyogenes were also investigated by ELISA in order to clarify the mucosal immume activity of middle ears affected by otitis media with effusion (MEE). The mean value of secretory IgA was 2712.6±1267.4μg/ml in mucoid MEE, and 854.6±1060.8μg/ml in serous MEE: while the mean value of serum type IgA was 2919±2308.9μg/ml in the mucoid group, and 4862.4±3387.4μg/ml in the serous group. These differences were statistically significant. The mean level of albumin concentrations in MEE was twice of that in sera. An appreciable antibody of secretory IgA to the M protein, which was between 11 to 68 ng/ml, was found in 17 of 77 (22%) mucoid MEE, and in 5 of 41 (12%) serous MEE. Findings of this study suggest that MEE is a muxture of secretions and transdate, that the accumulation of fluid, and water absorption, may occur in the tympanic cavity, and that middle ears affected by OME provide mucosal immunity preventing bacterial infection.