Immunohistochemical demonstration of Langerhans' cell in cholesteatoma using an antiserum against S-100 protein.

The epidermal Langerhans' cells play an important role in immunological reactions resulting from chronic inflammations of the skin. Recently, S-100 protein, one of the nervous-system-specific proteins, has been shown to be a useful marker for the epidermal Langerhans' cells. We investigated the localization of Langerhans' cells in human cholesteatoma specimens by means of an immunohistochemical method for detecting S-100 protein. A large number of Langerhans' cells containing S-100 protein immunoreactivity were found in the epithelium of the cholesteatoma and also in the subepithelial region. This immunoreactivity was detected both in the cytoplasm of the Langerhans' cells and their dendritic processes along their entire lengths. The number of S-100 positive Langerhans' cells in cholesteatoma associated with otorrhea increased significantly as compared with normal epithelium from the external auditory canal and tympanic membrane, while no increase in the number of S-100-positive cells was recognized in cholesteatoma without otorrhea. The S-100-positive dendritic cells in the cholesteatoma revealed longer and more complexly branched processes than those in normal tissues. These findings suggest that the Langerhans' cells within the cholesteatomatous lesion are responsible for generating and maintaining the chronic immunological reactions in this disease.