Interleukin-1 of Cholesteatomatous Keratinocytes

Abstract

Interleukin-1 (IL-1) has been thought to be one of the essential cytokines mainly produced by macrophages. It has recently been reported that epidermal keratinocytes produce IL-1, and attention is being paid to local immune reactions mediated with this cytokine. Interleukin-1 not only activates lymphocytes, but also acts as an osteoclast-activating factor. In this study, we used immunohistochemistry and immunoblotting on cholesteatomatous epithelium with anti-IL-1α antibody and anti-IL-1β antibody. Next, the relationship of cholesteatomatous debris to the production of IL-1 by keratinocytes was evaluated. Highly concentrated IL-1α was found in the cholesteatomatous epithelium, especially in the basal cell layer. The intensity of IL-1β staining was weaker than that of IL-1α staining. In the immunoblotting study, the 31 kd band, an intracellular immature precursor molecule, was identified. The production of IL-1α from keratinocytes was augmented to a greater degree by cholesteatomatous debris than by lipopolysaccharide or keratin. The keratinocytes did not produce IL-1β. These findings suggest that IL-1α is derived from cholesteatomatous keratinocytes. Interleukin-1, mainly IL-1α, from the stimulated cholesteatomatous keratinocytes may be an important factor in the markedly increased bone resorption observed in cholesteatoma.