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[Otosclerosis. A paramyxovirus-induced inflammatory reaction]
W Arnold1, H J Altermatt, R Kraft
1Klinik für HNO-Krankheiten, Kantonsspital Luzern.
Abstract:
Despite intensive investigation the cause of otosclerosis remains unknown. Recent immunohistochemical and electron microscopic studies of otosclerotic stapes have revealed a possible viral aetiology. Therefore we investigated the histology, ultrastructure and immunohistochemistry of fragments of otosclerotic footplates. Immunoglobulins G (IgG) and A (IgA) were found in plasma cells, oseocytes, chondrocytes and connective tissue of the active lesions. Polyclonal and monoclonal antibodies against paramyxovirus and rubella virus antigens produced reproducible reactions with these antigens at different sites of otosclerotic stapes, especially in the epithelial cells of the overlying middle ear mucosa. Using specific T-lymphocyte and B-lymphocyte markers about 80% of the lymphocytes present in the otosclerotic footplate proved to be T-lymphocytes. There was neither deposition of immunoglobulins nor any expression of viral antigens in non-otosclerotic footplates which were investigated as controls. Our results indicate that otosclerosis is an inflammatory reaction of the otic capsule initiated or caused by paramyxovirus and/or rubella virus. The silent progress of the disease and its onset under certain conditions, e.g. endocrine upsets, show similarity to slow viral infections.
Insights
Otosclerosis may be caused by paramyxovirus or rubella virus, triggering an inflammatory response in the otic capsule. This study found viral antigens and immune responses in otosclerotic stapes, suggesting a viral etiology for this hearing condition.
Area of Science:
- Otolaryngology
- Virology
- Immunology
Context:
- The etiology of otosclerosis, a common cause of hearing loss, remains largely unknown.
- Previous studies suggested a potential viral cause for otosclerosis.
- This research investigates the role of viruses in the pathogenesis of otosclerosis.
Purpose:
- To investigate the potential viral etiology of otosclerosis through histological, ultrastructural, and immunohistochemical analysis.
- To identify specific viral antigens and immune responses within otosclerotic stapes bone.
- To differentiate between otosclerotic and non-otosclerotic bone tissue regarding viral presence and immune markers.
Summary:
- Immunoglobulins G (IgG) and A (IgA) were detected in active otosclerotic lesions, alongside paramyxovirus and rubella virus antigens, particularly in middle ear mucosa.
- T-lymphocytes constituted approximately 80% of lymphocytes in otosclerotic footplates.
- Control bone samples showed no immunoglobulin deposition or viral antigen expression.
- Results suggest otosclerosis is an inflammatory reaction of the otic capsule, potentially initiated by paramyxovirus and/or rubella virus, similar to slow viral infections.
Impact:
- Provides evidence supporting a viral etiology for otosclerosis.
- Highlights the role of specific viruses (paramyxovirus, rubella) in the inflammatory process.
- Offers insights into the immunopathogenesis of otosclerosis, potentially guiding future diagnostic and therapeutic strategies.