EVIDENCE LINKING THE 68-KILODALTON ANTIGEN IDENTIFIED IN PROGRESSIVE SENSORINEURAL HEARING-LOSS PATIENT SERA WITH HEAT-SHOCK PROTEIN 70

Immunoblotting against bovine inner ear extracts has previously identi fied a 68 kd antigen reactive with 22% to 58% of sera of patients with rapidly progressive sensorineural hearing loss (PSNHL) of suspected a utoimmune causation. Efforts to purify and characterize this diagnosti c antigen suggest that it is ubiquitous rather than inner ear-specific , and may represent the highly inducible heat shock protein (hsp) 70. The antigens identified by PSNHL sera and anti-hsp 70 monoclonal antib odies copurify on ion exchange and adenosine triphosphate affinity chr omatography, and comigrate on one- and two-dimensional gel electrophor esis. Additionally, immunoblotting with positive patient sera shows dr amatically increased expression of the 68 kd antigen by bovine kidney cells following heat shock in culture. Reactivity with stress proteins of various classes has been reported in a number of autoimmune diseas es; however, anti-hsp 70 appears uniquely associated with ulcerative c olitis and PSNHL.