The effect of recent trauma on serum complement activation and serum C3 levels correlated with the injury severity score.

PURPOSE: The objective of this prospective pilot study was to estimate serum C3 levels and complement activation within 12 hours of injury and to correlate them with abbreviated injury score (AIS) so as to predict the outcome of injury in terms of mortality or sepsis. METHODS: The test group (n=30) of patients with < 12 hours of injury were assessed by the AIS-80 and compared with a control group (n=10). Serum C3 levels were estimated by the single radial immunodiffusion technique and complement activation by both two-dimensional and counter immuno-electrophoresis. Statistical analysis was performed using the correlation regression analysis and the minimum discrimination information statistics (MDIS) analysis. RESULTS: Serum C3 levels were not reduced in patients with injury severity score (ISS) < 12 (n=7). There was a statistically significant difference of serum C3 levels in patients with ISS between 12 and 29 (n=15) and in patients with ISS more than 29 (n=9). Complement activation also correlated well with ISS (p < 0.05). Complement activation and serum C3 levels were found to influence subsequent development of septic complications in the post injury period, being significantly lower in patients who developed septic complications. Complement alterations in trauma patients were a direct result of the trauma since they were not seen in patients undergoing surgery. CONCLUSIONS: ISS is a good prognosticator of outcome of trauma and serum C3 levels and complement activation are good predictors for mortality and development of septic complications in recently injured patients. These may prove to be effective parameters in the management of the patients with injury.