Immunologic aspects of otitis media.

The cellular immune response in otitis media with effusion consisted of granulocytic cells in the majority (60--70%) of cases, while the monocytic-lymphocytic cells formed the bulk of cells present in 20%. A considerable number (15--20%) of serous, seromucinous and mucoid effusions had sparse cellular populations. T-lymphocytes, marked with alpha-naphthyl-acetate-esterase (ANAE) constituted the majority of lymphocytes and were present in effusion liquids in numbers similar to those in blood. Tests with E-rosettes confirmed the results obtained with ANAE stain. The finding that T-lymphocytes are present in normal numbers may link the mucosal damage to the delayed-type hypersensitivity reaction. Another explanation of mucosal damage may be sought in immune complexes, which have recently been found to be present in many sterile middle ear liquids.