Epidermal interleukin 1 alpha functional activity and interleukin 8 immunoreactivity are increased in patients with...

Previous studies have suggested that epidermal-derived interleukin-1 is involved in the pathogenesis of cutaneous T-cell lymphoma (CTCL); however, the findings are conflicting and studies that combine immunohistochemistry and functional activity have not been performed. We investigated the interleukin-1 level in epidermis of patients with cutaneous T-cell lymphoma using both immunohistochemistry, enzyme-linked immunosorbent assays, and the thymocyte co-stimulation assay. Using supernatants obtained from epidermal cell cultures, we found a significant but small increase of interleukin 1 alpha protein release from involved CTCL epidermis compared to normal epidermis from healthy individuals. Both keratinocytes and leukocytes could release interleukin-1 alpha, but the majority was derived from the keratinocytes. Interleukin-1 beta protein was not detectable. In the thymocyte assay, interleukin-1 alpha was found to be biologically active. When lymphokines derived from a T-cell clone obtained from involved CTCL skin were co-cultured with epidermal cells, an enhanced release of epidermal interleukin-1 alpha could be demonstrated. Because interleukin 1 alpha was increased, we investigated the presence of interleukin 1-inducible keratinocyte-derived interleukin 8 and found it increased in CTCL epidermis compared to normal epidermis from healthy individuals. This study demonstrated an elevated epidermal IL-1 alpha level and IL-8 immunoreactivity in CTCL epidermis, which suggests that this elevated level is induced by lymphokines released from activated T cells.