The effects of inflammatory cytokines on the isolated human sebaceous infundibulum.

The human sebaceous pilosebaceous infundibulum was isolated and maintained in medium for up to 7 d. Freshly isolated infundibula were found to express keratins 1, 5, 6, 16, and 17, as determined by immunohistochemistry. In addition, freshly isolated infundibula expressed filaggrin, profilaggrin, involucrin, cornifin alpha, and loricrin. This pattern of expression was retained over 7 d. The addition of 100 U interferon (IFN)-gamma per ml over 3 d and 1 nM phorbol myristate acetate over 24 h resulted in the expression of intercellular adhesion molecule (ICAM)-1 and HLA-DR by infundibular keratinocytes, as determined by immunohistochemistry. Ten nanograms tumor necrosis factor-alpha per ml and 10 ng IL-6 per ml both caused expression of ICAM-1 alone. IL-1alpha had no effect on the expression of ICAM-1 or HLA-DR over 3 d, but addition of 1 ng IL-1alpha per ml over 7 d in culture resulted in hypercornification of the keratinocytes of the infundibulum, apparently brought about by early keratinocyte cornification. These data suggest that the isolated, maintained, infundibulum is a good model for studying the effects of inflammatory cytokines on the infundibulum, and that IL-1alpha acts on infundibular keratinocytes to promote cornification.