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.


BACKGROUND
Interleukin-6 is an integral cytokine mediator of the acute phase response to injury and infection. However, prolonged and excessive elevations of circulating IL-6 levels in patients after trauma, burns, and elective surgery have been associated with complications and mortality. The mechanistic role of IL-6 in mediating these effects is unclear.


METHODS
A review of current literature is performed to summarize the origins, mechanisms of action, and biologic effects of IL-6 and to characterize the IL-6 response to injury.


RESULTS
Interleukin-6 is a multifunctional cytokine expressed by a variety of cells after a multitude of stimuli, under complex regulatory control mechanisms. The IL-6 response to injury is uniquely consistent and related to the magnitude of the insult. Moreover, the early postinjury IL-6 response correlates with complications as well as mortality.


CONCLUSIONS
Interleukin-6 appears to play an active role in the postinjury immune response, making it an attractive therapeutic target in attempts to control hyperinflammatory provoked organ injury.
Department of Surgery, Denver General Hospital, Colorado 80204, USA.
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Biffl
E E
EE
Moore
F A
FA
Moore
V M
VM
Peterson
D015703:Antigens, CD / Q000502:physiology; D015415:Biomarkers; D002056:Burns / Q000276:immunology; D016207:Cytokines / Q000502:physiology; D006801:Humans; D007108:Immune Tolerance; D007249:Inflammation / Q000276:immunology; D015850:Interleukin-6 / Q000096:biosynthesis / Q000097:blood / Q000502:physiology*; D018123:Receptors, Interleukin / Q000502:physiology; D019947:Receptors, Interleukin-6; D015398:Signal Transduction; D013514:Surgical Procedures, Operative; D014947:Wounds and Injuries / Q000276:immunology* / Q000401:mortality
D015703:Antigens, CD; D015415:Biomarkers; D016207:Cytokines; D015850:Interleukin-6; D018123:Receptors, Interleukin; D019947:Receptors, Interleukin-6