COMPLEMENT ACTIVATION IN SUDDEN DEAFNESS

Objective: To test whether complement activation is associated with su dden deafness. Design: Plasma samples obtained from patients in the ac ute phase of sudden deafness were analyzed for comple ment activation measured by C3bc levels and terminal complement complex. Comparisons w ere made with plasma samples from healthy controls. Patients: Twenty-f ive adult patients with unilateral sudden deafness. The criteria for i nclusion were symptoms of hearing loss for not longer than 14 days and a hearing loss of 35 dB or more measured at entry. Results: Levels of C3bc were higher in patients compared with controls (P<.001). There w ere no differences in the formation of terminal complement complex in patients and controls. Conclusions: The elevated levels of C3bc in pat ients with sudden deafness indicate an activation of the first part of the complement cascade and therefore suspected inflammatory causes. M easurements of C3bc levels might identify patients with sudden deafnes s who would benefit from treatment with anti-inflammatory drugs.