Temporal Bone Histopathology and Immunoglobulin Deposition in Sjogren's Syndrome

Hypothesis: The histopathology of Sjogren's syndrome (SS) in the human inner ear correlates with mouse models of autoimmune inner ear disease. Background: SS is an autoimmune disease in which 25% of patients have sensorineural hearing loss (SNHL). The inner ear histology in a SS mouse model has shown degeneration of the stria vascularis (SV) and immunoglobulin G deposition on the basement membrane of SV blood vessels. Correlation with human temporal bone histopathology has not been addressed. Methods: The histopathology and immunohistochemistry of the inner ear in 4 patients with SS is described and compared with SS mouse models. Results: The histopathology of the inner ear in 3 patients with SS and SNHL showed severe loss of the intermediate cells of the SV and immunoglobulin G deposition on the basement membrane of SV blood vessels. These results parallel those of known SS mouse models. Additionally, there was shrinkage of the spiral ganglia neurons in 2 patients, whereas vestibular ganglia neurons were preserved. The fourth patient with SS and normal hearing showed only mild SV atrophy. Conclusion: This is the first study describing the pathologic changes in the inner ear of 4 patients with SS. The 3 SS specimens with SNHL showed pathologic changes in the SV similar to the mouse model of autoimmune inner ear disease. Additionally, we propose that spiral ganglia neurons may be directly affected by SS pathology. These results highlight the importance of correlating the histopathology of human temporal bones with animal models to better understand inner ear disease in future research.