Involvement of interleukin-1 in middle ear cholesteatoma

The histopathological characteristics of middle ear cholesteatoma are hyperproliferation and differentiation of the epithelium and accompanying destruction of the bones. We directed our attention to interleukin 1 alpha (IL-1 alpha) and demonstrated localization of IL-1 alpha in the epidermis of cholesteatoma. In addition, a comparative study was made of the relationship of IL-1 alpha with the developmental stage of cholesteatoma, the degree of destruction of the auditory ossicles, presence/absence of otorrhea, and the state of subepithelium.

Middle ear cholesteatoma tissues collected during operations were used as the experimental material, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blot, and immunohistological techniques were used as methods.

An anti-IL-1 alpha antibody-positive 17-kd band was observed in 2 of the 17 cases, whereas a 31-kd band was observed in 10 of the 17 cases. Neither the 17-kd band nor the 31-kd band was detected in normal skin tissues. The immunohistological staining showed the presence of IL-1 alpha in a region near the basal membrane of cholesteatoma epithelium.

A correlation was observed between IL-1 alpha and patients with vigorous proliferation of granulation in the subepithelium. The presence of granulation in the reverse side of the eardrum plays an important role in the proliferation of cholesteatoma epithelium.