Ultrastructural and immunohistochemical evidence of measles virus in active otosclerosis.

Because of the similarity between otosclerosis and Paget's disease of bone, and the mounting evidence of a viral cause in Paget's disease, we have investigated a possible viral cause for otosclerosis. Transmission electron microscopy of stapes footplate fragments with active otosclerosis has revealed structures morphologically identical with measles virus nucleocapsid in osteoblasts and preosteoblasts. Immunofluorescence and immunoperoxidase studies have confirmed the presence of measles nucleocapsid antigen in active lesions. Application of sera from patients with subacute sclerosing panencephalitis, a defective measles virus infection of the central nervous system, resulted in positive immunoreaction in areas of active otosclerosis.