Serum interleukin-6 and interleukin-10 responses in patients after major trauma: a prospective observational two centre study

Background: There is a need to develop objective risk stratification tools to define efficient care pathways for trauma patients. Biomarker-based point of care testing may strengthen existing clinical tools currently available for this purpose. The dysregulation of pro- and anti-inflammatory cytokines in the pathogenesis of organ failure is well recognised. This preliminary study was carried out to evaluate whether blood concentrations of IL-6, IL-10 and IL-6:IL-10 ratios in the early stages of the illness are significantly different in patients with worsening organ function. Methods: In this prospective observational cohort study, serum concentrations of IL-6 and IL-10 on days 1, 3 and 5 were measured in 91 major trauma patients using cytometric bead arrays. A composite measure of adverse outcome - defined as SOFA ≥ 2 or mortality at 7 days, was the primary outcome. IL-6 and IL-10 concentrations in early samples (days 1, 3 & 5) in patients who developed SOFA ≥ 2 on day 7 were compared against those who did not. Comparing cytokine concentrations against similar composite outcome groups at day 5 and in groups with worsening or improving SOFA scores (ΔSOFA) at Days 7 and 5 was undertaken as secondary analyses. Results: On day 7, 44 (48 %) patients showed adverse outcomes, associated with significantly greater IL-6 concentrations on days 1 and 5. (Day 1: 47.65 [23.24-78.68] pg/mL Vs 73.69 [39.93 – 118.07], P =0.040 and Day 5: 12.85 [5.80-19.51] pg/mL Vs 28.90 [8.78-74.08] pg/mL; P =0.0019). Similarly, IL-10 levels on days 3 and 5 were significantly greater in the adverse outcome group (Day 3: 2.54 [1.76-3.19] Vs 3.16 [2.68-4.21] pg/mL; P =0.044 and Day 5: 2.03 [1.65-2.55] Vs 2.90 [2.00-5.06] pg/mL; P <0.001). IL-6 and IL-10 concentrations were also significantly elevated in the adverse outcome groups on day 5. Conclusions: Early IL-6 and IL-10 concentrations are significantly greater in patients who develop worsening organ functions downstream. These differences may provide an alternate biomarker-based approach to further strengthen risk stratification in trauma patients.