Changes in Humoral Components of Host Defense Following Burn Trauma

Abstract

Serum opsonic activity for Escherichia coli 075, conversion of C3 [complement component 3] by inulin, total hemolytic complement (CH50), levels of native C3, factor B, C3b inactivator (KAF), properdin (P) and immunoglobulins (Ig) were determined in 14 patients with burns involving 13%- 91% body surface during 6-8 wk postburn. In the 12 uninfected patients, levels of IgG and IgA were reduced during the first 10 days postburn, and decreased concentrations of P and IgM were demonstrated from 3-6 wk postburn. C3 conversion was reduced from 10 days-6 wk postburn. Levels of C3 factor B and KAF were normal or elevated for the entire study period. No difference in the occurrence of humoral abnormalities was noted in patients with burns caused by flame, immersion scald or acid contact. Reduction in C3 conversion and P concentration were the only abnormalities which correlated with increasing burn size. Bacteremia and/or fungemia was documented in the other 2 patients. In 1 of these patients, reduction in CH50 occurred during septicemia due to Staphylococcus aureus, and in the other, reduction in all measurements of complement was associated with candidemia and Pseudomonas septicemia opsonic activity was only reduced significantly during sepsis, suggesting that this abnormality occurred as a result rather than a cause of infection. Consumption of components of the classical and/or alternative pathways of complement activation may be an important mechanism by which infection is perpetuated in the burn patient. The clinical management of the burn patient in preventing the development of septic complications was emphasized.