In cases of autoimmune inner ear disease, a Western Blot immunoassay has been recommended to identify serum antibodies that may be reacting against inner ear antigen(s). In 1990, Harris and Sharp reported the use of this technique in patients with progressive SNHL and found 35% to be positive for a specific anticochlear antibody in their serum.

In a group of patients who have unexplained progressive deafness, there is about one-third chance that an immune etiology underlies their hearing loss. Recent studies from the laboratory at UCSD of 279 patients with idiopathic bilateral SNHL found 90 (32%) to be positive by Western blot and of these, 63% were female. This is consistent with the female prevalence reported for other autoimmune conditions.

Antibodies to the 68kD antigen have also been demonstrated antibodies to the 68kD antigen in patients whose hearing improved on subsequent immunosuppressive therapy. They also report that 89% of patients with active progressive bilateral sensorineural hearing loss had antibodies to 68kD antigen, while those patients with inactive disease were uniformly negative. Of the Western blot-positive patients, 75% responded to steroid treatment, compared to an 18% response rate among patients who were 68kD antibody negative.

Recent studies have reported that the 68kD antigen is either a heat shock protein-70 (hsp-70) or an antigen associated with it. Quite independently, Block and colleagues found that hsp-70 was the protein identified when the 68kD antigen was sequenced. Thus, preliminary work now suggests that hsp-70 is either the target antigen of the autoimmune response or has a shared antigenic epitope or represents an epiphenomenon that develops as a byproduct of inner ear damage. Regardless of its source, the presence of this autoantibody in sera of patients with progressive deafness is diagnostic of an immune-mediated cause of deafness and apparently predicts steroid sensitivity.

In a retrospective study, Hirose et al have shown that Western blot hsp-70 antibody test is the best for predicting corticosteroid responsiveness.