Immunology and microbiology in acute otitis media

Various immunological parameters were measured in serum, middle ear fluid (MEF), and lymphocytes from peripheral blood and MEF of infants with acute otitis media due to S. pneumoniae or H. influenzae. Approximately half of 131 patients had IgE specific antibody to the infecting bacterium as determined by the indirect fluorescent antibody (IFA) technique. Seventy-one percent of these IgE positive patients had IgE specific antibody in the MEF. Total IgE concentration was found to be from an average of 1.5 to 3.0 times higher in the MEF when compared to the simultaneously drawn serum. In addition, antibody to pneumococcal capsular polysaccharides and to pneumococcal C-carbohydrate was demonstrated in the MEF by radioimmunoassay. When MEF specific antibody was compared to serum antibody it appeared that antibody to C-carbohydrate was more concentrated in the MEF. That this antibody was of the IgE class was suggested by IFA but not conclusively proven. Evidence exists that conditions for enhanced IgE synthesis is concomitantly associated with a decrease in T-cell activity. T-cell function in MEF derived lymphocytes as determined by rosette formation and by phytohemagglutinin (PHA) stimulation was approximately one-tenth that of the peripheral blood lymphocytes. However, that T-cells may participate in the immune response to polysaccharides was suggested by the observation that polysaccharide stimulated peripheral blood lymphocytes from infants immunized with octavalent pneumococcal capsular vaccine underwent protein synthesis two to three times that of the PHA stimulated cells. The clinical significance of this finding as well as the nature of the cell responsible for the increased protein synthesis remains to be established. It is hypothesized that acute otitis media results from local synthesis of bacteria specific IgE antibody which is enhanced by a paucity of local T-cell activity.