Inflammatory cell subpopulations in the middle ear mucosa of ears with effusion.

Middle ear mucosal biopsies were taken from 11 patients with middle ear effusion. In 8 cases the specimens were sufficiently large to allow detailed studies of the submucosal cellular components. It appears that in noncomplicated serous middle ear effusion, due to mechanical obstruction of the Eustachian tube, the submucosa is not infiltrated by inflammatory cells. In all types of mucoid effusion of variable duration, various lymphocyte classes, i.e. T- and B-lymphocytes and plasma cells, were present, suggesting a normal cellular immune response. The lack of granulocytes seems to indicate that there is no submucosal infection.