Secretory IgA and antibody activities in middle ear effusions.

Secretory IgA (SIgA) was isolated from pooled middle ear effusions (MEE) and its antigenicity and subunit structure were found to be identical to those of SIgA in saliva, nasal secretion and colostrum. The calculated percentage of SIgA in the total IgA of effusions was approximately 11%. Although the SIgA antibodies against streptolysin and staphylolysin were very low when compared to that of IgG class in effusion, this finding confirmed that MEE is at least partially a result of local immunologic reactions. The IgE concentration did not become elevated in both the MEE and serum obtained from patients with otitis media with effusion. Specific reaginic activity against mites was found in 5 of 56 (8.9%) MEE. Our findings would not suggest the significant role of atopic allergy in the formation of MEE.