Is there a correlation between the release of interleukin-12 and the clinical outcome of polytrauma patients?

Introduction: Interleukin-12-p70 (IL-12-p70) is a potent immunoregulatory cytokine composed of a heavy chain (p40) and a light chain (p35). Contradicting results have been reported with regard to leukocyte release and systemic concentration of IL-12 after polytrauma. Methods: We daily analyzed systemic concentrations of IL-12 in polytrauma patients (n = 37, mean ISS 33.9) in comparison to healthy donor values during intensive carl course by ELISA. Patients were divided according to their mean IL-12 levels into those with elevated IL-12 (group 1, n = 7), those with decreased IL 12 (group 21 n = 4) and those with IL-12 in the normal range (group 3, n = 26). Results: Patients in group 1 revealed elevated levels of IL-12 up to p70 > 1000 pg/ml and p40 > 2500 pg/ml. The common clinical feature of group I was a thorax trauma in combination with pneumonia (85 % survivors). Patients with single thorax trauma or pneumonia without thorax trauma (group 3) showed normal IL-12 values. Patients with decreased IL-12 levels revealed also a thorax trauma and pneumonia but all patients succumbed. The groups significantly differ in their stay in the intensive care unit, in TISS, in MODS score and in respiratory ratio, but not in ISS, mean CRP values and leukocyte counts. Correlation analysis revealed no significant relation between systemically altered IL-12 values and clinical parameters, with the exception of a negative correlation of p70 and ISS (r = -0.785) or MODS score (r = -0.314) in group 1. Conclusions: After major injuries there is no overall suppression of IL-12 formation. Patients with normal or elevated IL-12 levels belong mainly to the survivors, whereas patients with decreased IL-12 levels are at high risk of succumbing to multi-organ failure.