Sequential prospective analysis of the nonspecific host defense system after thermal injury.

The nonspecific host defense system of 66 patients with thermal injuries was studied prospectively. Our goal was to correlate the magnitude of injury with changes in host defenses and to determine if the responses of patients with and without sepsis were different. Eighteen patients experienced one or more septic episodes. Synchronous serial measurements of circulating fibronectin levels, neutrophil locomotive activity and phagocytosis, and intracellular killing in all patients showed that multiple components of the nonspecific host defense system were impaired after thermal injury. The depression of random migration and chemotaxis and the magnitude of the initial depression in serum fibronectin levels were related to the severity of injury but did not predict sepsis. Only a decrease in neutrophil bactericidal activity or a secondary depression in the serum fibronectin level was associated with the onset of sepsis.