IL-6 mRNA expression and IL-6 protein level. IL-6 mRNA expression and the IL-6 protein level were evaluated using expression profiles and receiver operating characteristic (ROC) curve analysis. (a) Transcriptional (n = 27) and translational (n = 20) profiles of IL-6 in serum are shown from POD 0 to 14 (CI: 95%), based on the relative expression ratio compared with β-actin mRNA. Bold solid line, bold dotted line, solid line, and dotted line depict IL-6 mRNA, IL-6, predictive cut-off level of IL-6 mRNA and mean of normal IL-6 level in plasma, respectively. (b) ROC curve analysis drawn between IL-6 mRNA and IL-6. Bold solid line, bold dotted line, dotted line, and solid line refer to IL-6 mRNA, IL-6, mean of normal IL-6 level in plasma, and predictive cut-off level of IL-6 mRNA, respectively. (c) SPSS software analysis of the AUC of the ROC curve was 0.809 and 0.453 for IL-6 mRNA and IL-6, respectively.