Initial posttraumatic monocytic cytokine expression in multiple injured patients: A flowcytometric analysis

Introduction: Depletion of monocyte (M(|>) function within the early posttraumatic phase has been proposed as one of the pivotal mechanisms of multiple organ failure development after multiple injuries (polytrauma). In that context, the reduced capacity of proinflammatory protein (e.g. cytokines) expression of (M(|>) upon stimulation may indicate immune system dysfunction. So far, the early posttraumatic phase is not well described. Hence, using flowcytometric analysis we investigated the initial posttraumatic intracellular de-novo synthesis capacity of TNFa, II-Ib and 11-8 expression in patients suffering from multiple injuries. Methods: In our prospective pilot study 5 patients were enrolled with blunt multiple injuries (Injury Severity Score >16 points); blood samples were drawn on admission and 12, 24, 48, and 72 hours after trauma. To determine the mediator production capacity whole blood was incubated with LPS (Sigma, St. Louis, USA) for 4 hours. (M<|>) were stained with anti-CD14 mAb (CD14-phycoerythrein-cyan-5 PC-5, Beckmann-Coulter, Krefeld, Germany). Intracellular monocytic TNFa, Il-lb and 11-8 were detected with phycoerythrein (PE) conjugated specific mAbs (PE, Hoelzel Diagnostika, Cologne, Germany). Cytokine positive (M(|)) were quantified by fluorescence activated cell sorter (FACS, Coulter, Krefeld, Germany). Data are given as percentage [%] of the whole (M<j>) population and compared by ANOVA on ranks and Student-Newman-Keuls test versus baseline levels. Results: The following table depicts LPS stimulated intracellular protein expression of TNFa, Il-lb, and 11-8 as measured by FACS analysis in whole blood monocytes indicating no significant decrease of cytokine production due to multiple trauma. The data are given as medians and the 25%-75% confidence interval; n=5 TNFa Il-lb 11-8 Oh 90(68-95) 65(48-74) 96(84-99) 6 h 86(65-95) 79(22-85) 95(76-96) 12 h 67(52-94) 42(24-74) 88(71-93) 24h 68(46-83) 42(11-75) 89(74-89) 48 h 65(52-93) 53(37-63) 78 (72-97) 72h 84(48-88) 56(46-62) 91(90-98) Conclusion: Although still preliminary, we demonstrated that no significant differences of the expression of TNFa, Il-lb or 11-8 compared to baseline levels is present in whole blood monocytes from multiple injured patients. However, since a certain trend of decreasing protein expression after 12h and 24h can be observed, further studies will be performed to increase patient numbers and to correlate the biochemical results with clinical signs of multiple organ failure.