Cytokine flow cytometry at the single-cell level has never been utilized in the study of adenoidal lymphocytes. We describe the multiparameter capability of flow cytometry to simultaneously detect an antigen on the surface of the adenoidal and peripheral blood lymphocytes and detect Th1 and Th2 cytokines within the cytoplasm of these lymphocytes. The data suggest that the percentage of cells producing interferon (IFN)-gamma are decreased in adenoidal as compared to peripheral blood lymphocytes, confirming our previous studies. The new findings show that the CD8 subset of adenoidal lymphocytes produces lower amounts of IFN-gamma as compared to peripheral blood CD8 cells. The intracytoplasmic synthesis of interleukin (IL)-2, however, appears to be similar in both adenoidal and peripheral blood lymphocytes. The CD4 subset of lymphocytes in the adenoid produces more IL-2, whereas the CD8 subset produces more IFN-gamma. Finally, as shown in our previous studies, the Th2 cytokines appear to be produced in similar quantities in both adenoidal and peripheral blood lymphocytes.