Interleukin 1

The last decade has witnessed a remarkable expansion in the understanding of the skin as an immunologic organ. A prime example of this is the discovery that keratinocytes can synthesize and secrete immunoregulatory and proinflammatory glycoproteins termed cytokines. Initial studies focused on interleukin 1-like molecules produced by keratinocytes, initially termed epidermal cell-derived thymocyte activating factor (ETAF). It is now clear that the functional activities described by the term ETAF are composed mainly of interleukin 1 alpha and interleukin 1 beta, although other epidermal cytokines may contribute to the biologic activity. The biologic properties of interleukin 1 are the basis of this review.