Validity of the Western blot immunoassay for heat shock protein-70 in associated and isolated immunorelated inner ear disease

OBJECTIVE: To assess the validity of the Western blot immunoassay for heat shock protein-70 (hsp-70) for diagnosis of autoimmune inner ear disease. STUDY DESIGN: Retrospective study of 53 patients affected by sudden deafness (n = 19), idiopathic progressive sensorineural hearing loss (n = 24), and Meniere's disease (n = 10) who were treated from 1995 to 1999. The clinical course and response to corticosteroid were evaluated. METHODS: A purified hsp-70 antigen from bovine kidney cell line was used for the Western blot immunoassay. RESULTS: Only five patients (9.4%) showed anti--hsp-70 antibodies: Two presented a sudden sensorineural hearing loss (sudden deafness group), two showed an idiopathic progressive sensorineural hearing loss (idiopathic progressive sensorineural hearing loss group), and one was affected by fluctuating hearing loss (Meniere's disease group). A systemic autoimmune condition was observed in 29.1% of patients with idiopathic progressive sensorineural hearing loss. CONCLUSIONS: The low sensitivity of Western blot immunoassay for patients affected by idiopathic progressive sensorineural hearing loss and Meniere's disease may result from either the long time elapsed from the hearing loss and vertigo to the initial examination or from the increased percentage of cases of systemic autoimmune disease present in patients with idiopathic progressive sensorineural hearing loss. More studies to detect the immune-mediated inner ear disease in Western blot immunoassay-negative patients are required.