Sequential serum complement (C3) and immunoglobulin levels in shock/trauma patients developing acute fulminant systemic sepsis

: The complement system has been implicated in the physiopathology of septic shock. Since infection is a major cause of death in trauma patients, we examined daily serum C3 and immunoglobulin levels in all victims of major trauma during a 3-month interval. Sixteen patients developed acute systemic sepsis 3-15 days after admission. For all variables the lowest values occurred shortly after hospital admission, during or just after fluid resuscitation. Thereafter, the serum C3 and immunoglobulin concentrations gradually returned to the normal ranges, despite the onset of fulminant systemic sepsis. Except for IgM, the occurrence of hypotension during sepsis did not affect the recovery patterns of the measured variables. In the five patients experiencing hypotension, serum IgM dropped transiently but resumed its normalization trend after the restoration of adequate perfusion pressure. In the three nonsurvivors there was no reduction in the serum C3 or immunoglobulin levels prior to death. These data do not support a role for C3 or the immunoglobulins in the pathogenesis of acute fulminant clinical sepsis. On the contrary, the behavior of these substances during severe sepsis is more consistent with protective host defense functions.