PR-2. ANTIMEASLES IGG FOR SEROLOGIC DIAGNOSIS OF OTOSCLEROTIC HEARING LOSS

Tamas Karosi, Jozsef Konya, Mihaly Petko (University Medical School of Debrecen), Laszlo Z. Szabo (National Health Center), Jozsef Pytel (University Medical School of Pecs), Jozsef Jori (University Medical School of Szeged), Istvan Sziklai (University Medical School of Debrecen, Hungary)

 

Objectives: Otosclerosis is a disease of unknown etiology causing progressive conductive hearing loss. Persistent measles virus infection of the otic capsule is suggested to be an etiologic factor in otosclerosis. Diagnostic methods of otosclerosis are sensitive to ossicular chain fixation with low specificity for otosclerotic stapes ankylosis.

Methods: Nucleic acid was extracted from stapes footplates of clinically stapes fixation patients (N=213). Measles virus nucleoprotein RNA was amplified by RT-PCR. Amplification results were correlated to histological findings in 49 cases. Antimeasles IgG levels of all clinically stapes fixation as well as control sera specimens were measured by ELISA.

Results: Among clinically stapes fixation patients, 141 stapes footplates contained measles virus RNA. Among 49 histological specimens, viral RNA was detectable only in histologically otosclerotic stapes footplates (N=35). Histology for virus negative footplates (N=14) excluded otosclerosis. Antimeasles IgG levels were significantly lower in the sera of patients with virus positive stapes compared with control sera.

Conclusions: Combination of decreased antimeasles IgG serum level and conductive hearing loss has a great specificity and sensitivity as a diagnostic method in preoperative evaluation of ossicular chain fixations. Low antimeasles IgG level indicates otosclerosis, whereas high level suggests non-otosclerotic ossicular chain fixations. Preoperative elucidation of the etiology of a conductive hearing loss may suggest optional medical treatment in preference to surgical methods.          

* Contact person email: karosi@freemail.hu