Human recombinant interleukin-1 alpha is proinflammatory in normal human skin.

The proinflammatory effects of recombinant human interleukin-1 alpha (HRIL-1 alpha) have been determined in the skin of normal human volunteers. Intradermal injection of 10, 50 and 100 U HRIL-1 alpha produced dose-related erythema which first appeared at 2 h, was maximal around 24 h, persisted for up to 48 h, and was associated with oedema. Histological examination revealed dermal mononuclear cell infiltrates, which were accompanied by neutrophils at 4 and 8 h. Injection of heat-treated HRIL-1 alpha (100 U) produced no erythema or oedema. These results demonstrate the potent proinflammatory properties of HRIL-1 alpha in human skin.