The studies in this proposal are designed to identify biochemical abnormalities in polymorphonuclear leukocyte function in patients with major thermal trauma and to establish the role of these abnormalities to sepsis in burn patients. Oxidative and non-oxidative mechanisms of the host defense system such as O2 consumption, NAD (P) H oxidase activity, O2 minus, H2O2, myeloperoxidase, glucose -6- phosphate dehydrogenase and glutathione are being examined. The role of serum components, compliment, etc. will be analysed and all determinations related to post burn day and presence or absence of sepsis. Through these investigations and the isolation of the responsible agents in decreased leukocyte function it is hoped preventative and/or corrective treatment regimens can be devised.