Reduction in alternative complement pathway mediated C3 conversion following burn injury.

Studies were performed to further investigate an abnormality of the alternative complement pathway associated with burn injury. C3 conversion by inulin and cobra venom factor was measured in serial serum samples from 18 burned patients and in the sera from 25 normal controls. C3 conversion by both activating substances in the patients' sera was significantly decreased during 50 days postburn in comparison to C3 conversion in the normal sera. The most marked reduction in C3 conversion occurred in patients with large full-thickness injuries and infectious complications. However, the abnormality was not more severe in patients with pneumonia and bacteremia in comparison to patients with bacteremia only. It was also not predictive of fatal outcome resulting from infectious complications. Preliminary evidence was presented to suggest that the abnormality is caused by a serum inhibitor, which has an affinity for cellulose and/or is inactivated by it.