Immediate IL-10 expression following major orthopaedic trauma: relationship to anti-inflammatory response and subsequent development of sepsis

Objective: To assess the relationship between IL-10 release and anti-inflammatory response following blunt trauma. Design: Prospective longitudinal clinical study. Setting: Departments of trauma and anaesthetics in a university teaching hospital Patients: Forty-eight adult patients with a mean injury severity score of 14.5 (range 9-57) were prospectively studied following blunt trauma. Measurements and results: Venous blood samples were collected on arrival and at 16 and 24 h, and at 3, 5, and 7 days. Peripheral blood mononuclear cell (HLA-DR) expression on CD14 + monocytes was quantified by flow cytometry and serum IL-10 was assayed by ELISA. Anti-inflammatory response was defined as monocyte HLA-DR expression of less than 30 % of that seen in healthy controls. Serum IL-10 levels in trauma patients on arrival was significantly elevated, 70.0 [48.0-92.1, 95 % confidence interval, (CI)] compared to the control group, 3 (0-5) (P < 0.0001), and monocyte HLA-DR expression was significantly lower, 14.2 (12.1-16.3, 95 % CI), in patients versus 25.2 (22.4-28.1) in controls (P < 0.001). Patients with low HLA-DR expression (n = 14) had significantly higher serum IL-10 levels than those whose HLA-DR expression remained above 30 % of the control value (n = 34), (P < 0.038). In patients who developed sepsis (n = 11), serum IL-10 levels were greater on admission, [143.7 (80.2-207.2) pg/ ml-1], and remained elevated during the study period compared with non-complicated patients, [50.16 (33.5-66.8) pg/ml-1]. Immediate IL-10 (2 h following trauma) was negatively correlated with simultaneous HLA-DR expression, (r = -0.49, P = 0.0005). Conclusion: These findings support the view that IL-10 release regulates monocyte HLA-DR expression and may be related to an anti-inflammatory response and development of sepsis following trauma.