Among epidermal cytokines, IL-1 and TNF alpha are involved in inflammatory skin reactions and suspected of modulation by immunosuppressive treatment (e.g., cyclosporin A, CsA) or UVB-irradiation, 2 mediators probably being involved in epithelial carcinogenesis. We evaluated the effects of 8 micrograms/ml CsA and 100 J/m2 UVB-irradiation on the production and secretion of IL-1 and TNF alpha on normal human epidermal keratinocytes (NHK) and epidermal keratinocyte cell lines either spontaneously transformed (HaCaT) or transformed by human papillomavirus (HPV) type 16 or 18 (EK 16 and EK18), by using ELISA test. Normal and immortalized keratinocytes constitutively produced and released IL-1 alpha, IL-1 beta and IL-1 receptor antagonist (IL-1RA) but IL-1 synthesis by NHK was significantly higher than by cell lines. All the cells spontaneously excreted low amounts of TNF alpha. Different responses to treatments were evidenced between NHK and cell lines. CsA modified significantly the production and secretion of IL1 in most cells whereas slight changes were observed with TNF alpha secretion. UVB irradiation had no effect on the intracellular IL1 pool of any cells but increased the release of IL1 and TNF alpha. The association CsA-UVB did not result in additive effects on synthesis and secretion of IL1; the release of TNF alpha by the cells remained poor except for EK18 cells. Taken together, these results show that, in immortalized keratinocytes, the IL-1 and TNF alpha expression was differently affected by treatments with CsA and/or UVB-irradiation as compared to NHK. In addition, spontaneously transformed keratinocytes, HaCaT, reacted differently from HPV-transformed keratinocytes, EK16 and EK18.