SERUM ANTIBODY TO INNER-EAR PROTEINS IN PATIENTS WITH PROGRESSIVE HEARING-LOSS - CORRELATION WITH DISEASE-ACTIVITY AND RESPONSE TO CORTICOSTEROID TREATMENT

Objective.-To test whether detection of serum antibody to a 68-kd inne r ear protein distinguishes among different causes of sensorineural he aring loss, and identifies patients with active disease and those like ly to respond to corticosteroid therapy. Design.-Serum samples were te sted by Western blot using bovine inner ear extract as antigen, and re sults were correlated with patient information obtained by chart revie w. Setting.-Referral center. Subjects of Study.-Serum samples were obt ained from patients with idiopathic, progressive, bilateral sensorineu ral hearing loss (IPBSNHL) (n=72) otosclerosis (n=11), Cogan's syndrom e (n=8), patients with positive tests for antinuclear antibodies (n=10 ), and normal controls (n=53). Main Outcome Measure.-Detection of seru m antibody to a 68-kd inner eat protein. Results.-Serum from 42 of 72 patients with IPBSNHL reacted with a 68-kd protein constituent of inne r ear extract. This reactivity was not detected in serum from 11 of 11 patients with otosclerosis, or in eight of eight with Cogan's syndrom e. It was found in serum from one of 10 patients with a positive test for antinuclear antibody and in one of 53 normal controls. Antibody to the 68-kd protein was detected in serum from 89% of patients with act ively progressing IPBSNHL and none of the 25 patients with inactive di sease (P<.001). Patients who were antibody-positive responded to stero id treatment more frequently than did those who were antibody-negative (P<.001). Conclusions.-These results indicate that the presence of ci rculating antibody to a 68-kd constituent of bovine inner ear extract serves as a marker for IPBSNHL and that its presence correlates with d isease activity and responsiveness to corticosteroid treatment.