Autoimmune-mediated sympathetic hearing loss: a case report.
BACKGROUND
Damage to one inner ear is occasionally followed by contralateral sensorineural hearing loss. This has been defined as sympathetic hearing loss.


OBJECTIVE
It is hypothesized that autoimmunity can play a role in the pathogenesis of sympathetic hearing loss.


METHODS
A male patient who developed right-sided sympathetic hearing loss at 20 years of age, 11 years after deafness of the left ear caused by a temporal bone fracture, is described. The patient's serum was analyzed for the presence of autoantibodies against inner ear tissues by immunocytochemistry and Western blotting using rat inner ear tissues. The patient's serum was tested specifically for antibodies against heat shock protein 70 by immunodot blot. The presence of autoantibodies known to play a role in systemic autoimmune disease was also examined.


RESULTS
Immunocytochemistry on rat temporal bone sections demonstrated autoantibodies in the patient's serum specifically targeted against cochlear outer hair cells. No reactivity of the patient's serum was observed with control tissues including kidney, brain, and liver. Western blotting using homogenized rat cochlear tissues showed that the patient's serum reacted with a 25- and 27-kDa protein. No reactivity was observed with heat shock protein 70 in the immunodot blot analysis. The patient's serum did not contain autoantibodies against antinuclear antibodies, double-stranded DNA, antineutrophil cytoplasmic antibodies, basement membrane, reticulin, intestinal mucosa, muscle, collagen, or mitochondria.


CONCLUSIONS
Observations indicate that this patient suffered sympathetic hearing loss caused by organospecific autoimmunity directed to cochlear outer hair cells.
ten Cate
Wouter-Jan F
WJ
Department of Otorhinolaryngology, University of Essen, Germany. wouter-jan.tencate@middlemore.co.nz
Bachor
Edgar
E
D000328:Adult; D000818:Animals; D001301:Audiometry, Pure-Tone; D001323:Autoantibodies / Q000097:blood; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D015153:Blotting, Western; D003937:Diagnosis, Differential; D018072:Hair Cells, Auditory, Outer / Q000276:immunology / Q000473:pathology; D006312:Hearing Loss, Bilateral / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007105:Immune Complex Diseases / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D007124:Immunoenzyme Techniques; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012887:Skull Fractures / Q000150:complications; D013701:Temporal Bone / Q000293:injuries
D001323:Autoantibodies