Detection of circulating tumor necrosis factor after endotoxin administration.

TL;DR: It is concluded that the response to endotoxin is associated with a brief pulse of circulating tumor necrosis factor and that the resultant responses are effected through the cyclooxygenase pathway.

Abstract: Cytokines, products of stimulated macrophages, are thought to mediate many host responses to bacterial infection, but increased circulating cytokine concentrations have not been detected consistently in infected patients. We measured plasma concentrations of circulating tumor necrosis factor alpha (cachectin), interleukin-1β, and gamma interferon, together with physiologic and hormonal responses, in 13 healthy men after intravenous administration of Escherichia coli endotoxin (4 ng per kilogram of body weight) and during a control period of saline administration. Eight additional subjects received ibuprofen before receiving endotoxin or saline. Plasma levels of tumor necrosis factor were generally less than 35 pg per milliliter throughout the control period, but increased 90 to 180 minutes after endotoxin administration to mean peak concentrations of 240±70 pg per milliliter, as compared with 35±5 pg per milliliter after saline administration. Host responses were temporally associated with the in...