The analysis of the PMN receptor expression was started within two hours after the blood sample was obtained. The expression of the above mentioned markers was measured as described previously [9]. Expression of active FcγRII by FITC-labeled MoPhab A27 was measured after 5 minutes of stimulation of whole blood at 37°C with N-formyl-methionyl-leucyl-phenylalanine (fMLP 10-6M) to evaluate the responsiveness of the cells for a bacterial

Adriamycin ic50 derived activating agonist. After stimulation, the samples were put on ice again and analyzed. Blood samples were stained with fluorescein isothiocyanate (FITC) directly labeled antibodies (MoPhab A27) as described previously [9]. The expression of CD11b and HLA-DR were performed according the recommendations of the manufacturer. In short, directly labeled antibodies were added 1:20 to whole blood and incubated for 60 minutes on ice. After incubation, the red cells were lysed with ice-cold isotonic NH4Cl. After a final wash with PBS2+

(PU-H71 concentration phosphate buffered saline with added sodium citrate (0,38% wt/vol) and isotonic pasteurized plasma proteins (10% vol/vol), the cells were analyzed in a FACScalibur Flowcytometer (Becton & Dickenson, Mountain view. CA). The PMNs and monocytes were identified according to their specific side-scatter and forward-scatter signals. Data from individual experiments are depicted as histograms of fluorescence intensity in arbitrary units (AU) or summarized as the median channel fluorescence (MCF) of at least 10000 events. Interleukin-6 IL-6 was determined using a human IL-6 sandwich ELISA (Endogen, Pierce Biotechnology, IL, United States) according find more to the procedures prescribed by the manufacturer. Detection limit of this ELISA was 5 pg/ml. Statistical Analysis check All data were analyzed using SPSS version 15.0 software (The Apache Software Production 2008, Chicago, Illinois). Results are expressed by medians + range. Statistical analysis was performed using a non-parametric Mann Whitney U Test for two

groups and a Kruskall Wallis H test for multiple comparisons. Paired analysis (before and after surgery) was performed using Wilcoxon Signed Ranks test. Statistical significance was defined as p < 0.05. Results Demographics A total of 45 patients fulfilled the inclusion criteria in a period of 1 year. Of these 45 patients, 3 patients were missed due to logistical restrictions, 2 patients underwent external fixation initially, but did not receive conversion to intramedullary osteosynthesis, 1 patient did not give consent and in 1 patients sampling was flawed. Thus, 38 patients were adequately followed up (84%). Their median ISS was 13 (range 9-43) and their median APACHE II Score was 5 (range 0-25) at admission. Intramedullary nailing was performed either directly or in a staged damage control approach. Seven patients developed ALI/ARDS, which indicates an adequate patient selection. Further demographics are listed in Table 1.