Endotoxin and tumor necrosis factor-alpha-induced interleukin-8 release in humans.

Neutrophil recruitment and activation are thought to play an important role in tissue damage observed in septicemia. Interleukin-8 (IL-8) is a small cytokine with important neutrophil-activating and chemoattractant properties. IL-8 release was studied after injection of human volunteers with low doses of either endotoxin (2 ng/kg of body weight) or tumor necrosis factor-alpha (TNF alpha) (50 micrograms/m2). After TNF-alpha injection, IL-8 appeared at 30 min, whereas increased levels were first observed after 90 min in endotoxin-challenged volunteers. Peak levels were measured at 120 min after both endotoxin (192 +/- 193 ng/L) and TNF alpha (500 +/- 236 ng/L) injection. These data indicate that IL-8 is released in humans after injection of endotoxin and TNF alpha and suggest that endotoxin-induced IL-8 release is mediated by TNF alpha.