INTERLEUKIN-6 IN THE INJURED PATIENT MARKER OF INJURY OR MEDIATOR OF INFLAMMATION

Objective The effects of interleukin (IL)-6 in the injured patient are examined in an attempt to clarify the potential pathophysiologic role of IL-6 in the response to injury. Summary Background Data Interleuki n-6 is an integral cytokine mediator of the acute phase response to in jury and infection. However, prolonged and excessive elevations of cir culating IL-6 levels in patients after trauma, burns, and elective sur gery have been associated with complications and mortality. The mechan istic role of IL-6 in mediating these effects is unclear. Methods A re view of current literature is performed to summarize the origins, mech anisms of action, and biologic effects of IL-6 and to characterize the IL-6 response to injury. Results Interleukin-6 is a multifunctional c ytokine expressed by a variety of cells after a multitude of stimuli, under complex regulatory control mechanisms. The IL-6 response to inju ry is uniquely consistent and related to the magnitude of the insult. Moreover, the early postinjury IL-6 response correlates with complicat ions as well as mortality. Conclusions Interleukin-6 appears to play a n active role in the postinjury immune response, making it an attracti ve therapeutic target in attempts to control hyperinflammatory provoke d organ injury.