Leukocyte responses to injury.

Injury elicits a response from all cells of the immune system in which cytokines and other metabolic products of activated leukocytes can act either beneficially to provide for enhanced host resistance or deleteriously to depress the function of remote organs and cause what has been termed systemic inflammation. These at times antithecal responses of leukocytes that appear to integrate postinjury changes in the neuroendocrine, immune, and coagulation systems have been implicated as principal causative factors in multiple systems organ failure. Numerous investigators have evaluated a variety of therapeutic agents to prevent and control infection by restoring leukocyte function, while others have evaluated antagonists and monoclonal antibodies as a means of controlling the exaggerated and persistent actions of leukocytes and cytokines caused by systemic inflammation. The redundancies of the cell populations and the cytokines and other metabolites produced by the cells predictably limit the effectiveness of any single agent and make clinical evaluation of such agents difficult.