This study was designed to identify differences in the immunological reactions in adenoid tissue between children suffering from chronic secretory otitis media (SOM) and control children without ear disease. Cell populations were identified using monoclonal antibodies and flow cytofluorometry to facilitate quantitative comparisons. A modification of the FOG method was developed to quantify lymphocytes with intracellular IgG and IgA. Immunological screening was done in the first part of the study. No significant differences were found between the groups regarding cells positive for CD3, CD4, CD8, CD20 or CD25. A significantly higher number of PCA-1 positive cells (presumably plasma cells) were found in the SOM group. The second part of the study concentrated specifically on cells containing IgG or IgA. No statistically significant differences in number of positive cells were found between the groups. When we related the percentage of positive cells to age, a statistically significant decrease with age for IgA-positive cells was found in the SOM group but not in the control group. This result supports the hypothesis that SOM is associated with an immunological reaction that influences immunoglobulin production in adenoid tissue.