The purpose of this study is to help improve our understanding of the biology involved in the body's response to serious trauma or burn injury. The host response to trauma and burns is a collection of physiological and pathophysiological processes that depend critically upon the regulation of the human innate immune system, with particular emphasis on the inflammatory component of that system. No single research center or small group of centers has the capacity to delineate the integrated response of this complex biological system, which involves multiple molecular and genetic interactions that vary in time. Our proposal promotes the identification of important dynamic relationships that regulate the integration of this complex biological system, with the expectation that this understanding will ultimately impact the diagnosis, prognosis, and treatment of the hospitalized, severely injured patient.