Epidermal cytokine mRNA expression induced by hapten differs from that induced by primary irritant in human skin organ culture system.

Epidermal cells produce various kinds of cytokines and express cell adhesion molecules. To analyze early events which induced in human epidermis by stimulation with various chemicals, we analyzed mRNA of cytokines expressed in epidermis in a human skin organ culture system. After painting haptens, primary irritants or vehicle control on human skin specimens sliced to 1 mm thickness and cut into approximately 5 x 5 mm blocks, the pieces were cultured in serum-free medium. After separating epidermis from dermis, total RNA was extracted and mRNA of cytokines was assessed by the reverse transcriptase-poly-merase chain reaction. Only haptens induced IL-1 beta mRNA at 1-3 hours. TNF-alpha mRNA was induced 9 hours after application of haptens and 1 hour after application of primary irritants. IL-1 alpha mRNA was not induced by either haptens or primary irritants. Thus, cytokine mRNA expression induced by haptens in epidermis differs from that induced by primary irritants.