Immunohistologic findings in otosclerosis.

The cause of otosclerosis is still unclear. Between 1981 and 1988 we obtained 186 biopsy specimens of otosclerotic bone during the course of stapedectomies. Serial sections of the specimens were examined histologically (H & E) and immunohistologically (peroxidase-antiperoxidase technique) for immunoglobulin G, immunoglobulin M, and C1q and C3 complements. Active otosclerotic foci were found in 61 cases, 43 of which had IgG deposits. IgM antibodies were absent. In specimens with inactive otosclerosis, IgG and IgM were not evident, C1q and C3 complements were demonstrated together with IgG, but sometimes also in the mucosa independent of the phase of the otosclerosis. Our findings suggest that an immunologic process may be important in the pathogenesis of otosclerosis.