In vitro effects of complement inactivation upon burn-associated cell-mediated immunosuppression

Serum of severely burned patients possesses in vitro capacity to suppress cell-mediated immunologic responses. Failure to establish immune competence is predictive of mortality, usually from sepsis. In this investigation, the hypothesis that complement fragments, known to be elevated in the acute phases of burn injury, contribute to this suppression is tested. Serum taken from patients with massive (greater than 60%) and major (less than or equal to 60%) burn injury was analyzed for the ability to suppress mitogen-induced lymphocyte blastogenesis before and after exposure of the burn serum to (complement inactivating) temperatures. All patients in this study had immune suppressive serum. Heat inactivation partially restored immune competence in the serum of all patients, though significantly more so in patients with major burns compared with those with massive burns. Complement appears to play a contributory role in the acute stages of burn-induced, cell-mediated immunosuppression, though its role in patients with massive burn injury is overshadowed by the presence of serologic suppressive factors not present (or present in lower concentration) in patients with major burns.