[Determination of IL-6 in serum and perilymph during inner ear immune response]

During secondary inner ear immune responses against keyhole limpet hemocyanin (KLH), to understand the change of interleukin-6 (IL-6) levels in perilymph and serum, IL-6 levels in perilymph and serum were investigated using an immunoassay. No IL-6 levels were detectable at Day 0 in perilymph. The earliest perilymph IL-6 levels were observed after 6 h, peaking at 24 h, and then decreasing gradually. IL-6 level remnants were detected at 7 days in perilymph. In contrast, during this observation period, low IL-6 levels were only detectable in perilymph from control ears, disappearing after 72 h. IL-6 levels don't change in serum. Previous study has identified the endolymphatic sac (ES) lags behind the earlier appearance of intercellular adhesion molecule-1 (ICAM-1) in the spiral modiolar vein and spiral ligament during immune response. The present study not only provides further support for the existence of an inner ear immune response which is regulated by cytokines, but also supports that cytokines controlling expression of adhesion molecules are released probably by cells which located out of ES.