Immunohistochemical evidence of measles virus antigens in active otosclerosis.

Despite intensive investigation, the cause of otosclerosis remains uncertain. Recent studies of Paget's disease of bone have revealed a possible viral origin. Because of similarities between otosclerosis and Paget's disease, we have pursued investigation of a possible viral cause of otosclerosis. Four temporal bone specimens from patients with otosclerosis, processed for immunohistochemistry, demonstrated positive specific reactivity with monoclonal antibodies to measles virus antigens using the indirect immunofluorescent and immunoperoxidase techniques. Reactivity was most intense in active foci. Reactivity in the peroxidase assay was also observed in areas of acting otosclerosis with application of primary antisera from patients with subacute sclerosing panencephalitis, a disorder of the central nervous system in which a defective measles virus has been isolated. Other related paramyxoviruses, including mumps and respiratory syncytial virus, were negative, as were negative controls.