Autoimmunity in Sudden Sensorineural Hearing Loss: Possible Role of Anti-endothelial Cell Autoantibodies

Abstract

In order to verify whether anti-endothelial cell autoantibodies (AECAs) can be used as serological markers of inner ear vasculitis in sudden sensorineural hearing loss (SSHL), 32 patients affected by idiopathic SSHL were investigated. All patients underwent a routine general physical examination and extensive audiovestibular, microbiological and immunological investigations. Fourteen normal subjects without a history of HL, autoimmune or metabolic disease served as controls. Detection of AECAs was performed using an indirect immunofluorescence technique. AECA-positive patients were treated with methylprednisone, while AECA-negative patients were treated with a combined regimen of steroids, plasma expander and aspirin. The average hearing recovery for 5 frequencies (0.25-4 kHz) was analyzed in each subject 1 month after treatment and every 3 months thereafter; median follow-up was 12 months (range 9-18 months). A total of 15/32 patients (46.8%; 11/19 females, 4/13 males) were AECA-positive and thus differed significantly from the normal population in whom only 2/14 tested cases were positive ( p =0.03). Severe hearing loss was associated with being AECA-positive in 8/11 cases. During follow-up, 25/32 patients improved their hearing and 17 of these patients were AECA-negative. The seven cases without hearing improvement were all AECA-positive. In patients with SSHL, immune-mediated vascular damage may have a pathogenetic role and AECAs may represent a serological marker of vasculitis even if they are not inner ear-specific and even if they represent an epi-phenomenon rather than the only cause of SSHL.