Lymphocyte morphology in mucoid middle ear effusions.

Cytologically, the mucoid middle ear effusions could be divided into a lymphocyte-monocyte type and a type where the granulocytes predominated. By alpha-naphthyl-acetate esterase (ANAE) staining procedure the T lymphocytes were found to make up the majority of lymphocytes in the first type, often accompanied by large numbers of ANAE-positive macrophages. In the second type the relative and particularly the absolute numbers of T cells were smaller. The T lymphocytes in aural effusions, distributed in agreement with their normal distribution in blood, could be the basis of possible delayed hypersensitivity immune mechanisms in the middle ear, but definite proof, either demonstrating receptor molecules directed to antigens or a specific response by T cells, is still lacking.