Immune response to acute otitis media in children III. Implications of viral antibody in middle ear fluid.

With the technique of radioimmunodiffusion and indirect FA staining, IgA antibody to measles, mumps, rubella, and polio-1 were determined in serum and middle ear fluid (MEF) of 103 patients with otitis media. The occurrence of IgA viral antibody in MEF and its absence in simultaneously drawn serum was used as an indicator of local antibody production. Of the 401 assays performed, 41 instances of IgA antibody exclusively in MEF were found. Only four of these occurred in specimens from unimmunized patients and were directed against rubella virus. Of the 37 remaining cases, 16 each were directed against measles and polio-1 and four and one, respectively, for mumps and rubella viruses. The mean specific IgA titers were from 8- to 17-fold higher in MEF from immunized individuals than in the unimmunized and persisted for at least 9 to 19 months after immunization. The data thus indicate 1) specific immunologic sensitization of the middle ear mucosa can be achieved by parenteral as well as oral routes of immunization, and 2) specific immunologic memory exists in the middle ear mucosa. These two factors are crucial to feasibility of immunization against acute otitis media.