Immunology of the tympanic membrane.

Under normal conditions, tympanic membranes lack immunocompetent cells, except mast cells and Langerhans cells in the pars flaccida, and the annular and manubrial regions of the pars tensa. Lymphocytes migrate to these regions after the induction of immune-mediated otitis media, although the other regions of the pars tensa do not show the presence of these cells. Langerhans cells appear throughout the entire tympanic membrane, in case of otitis media. The unique features of the immunological aspect of the tympanic membrane are discussed.