Complement Activation, C3 and Interleukin-6 Levels as Prognostic Markers in Polytraumatized Patients

Abstract

CONTEXT/BACKGROUND:The management of polytraumatized patients is always challenging to the clinician due to high risk of sepsis, multi-organ failure and death. AIM: Our objective was to study Complement activation, C3 and IL-6 levels in trauma patients so that clinical outcome can be predicted for proper management of injury. SETTINGS AND DESIGN: This case-control study was conducted in the Department of Microbiology, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh. MATERIALS AND METHODS: 44 trauma patients and 40 healthy controls, selected on a random basis, were included in this study. Blood was collected within 24 hours and at 7 th day of injury. Complement activation was determined by Countercurrent Immunoelectrophoresis and Crossed Electrophoresis. C3 levels were measured using Single Radial Immunodiffusion. IL-6 was detected by ELISA. STATISTICAL ANALYSIS USED: Unpaired "t" test and Chi-square test were used to analyze the data statistically. Probability values less than 0.05 were considered significant. RESULTS: All patients showed complement activation within 24 hours of injury. Patients with Injury Severity Score (ISS) ≥15 had lower C3 as compared to controls (p < 0.001) and those with ISS <15 (p < 0.001). Patients with ISS ≥30 continued to have activated complement and low C3 in 2 nd week; they subsequently developed infection. Complement was inactive and C3 levels recovered in patients with ISS <30. Non-survivors showed lower C3 than survivors (p < 0.05). Patients with infection had lower C3 than those who remained free of infection (p < 0.05). All patients with ISS ≥15 showed initial elevation in IL-6 levels. Patients with ISS ≥45 had higher IL-6 than controls (p < 0.001) and those with ISS <45 (p < 0.05). Non-survivors had higher IL-6 than survivors (p < 0.05). Patients who developed infection showed higher IL-6 than those without infection (p < 0.001). CONCLUSIONS: Complement activation, C3 and IL-6 levels correlated well with severity of injury and development of infection. Serial estimation of complement activation status, C3 levels and IL-6 levels are useful tools in monitoring the clinical progress of trauma patients as these parameters vary significantly with respect to the severity of injury and the development of local and systemic infection in such patients. Hence, they can be used to decide timely the course of therapeutic interventions, predict the onset of infection/septicemia and mortality in polytraumatized patients.