RESULTS: The level of IL-35 increased significantly in sepsis-related ARDS patients, especially in severe subgroup and nonsurvivors. Elevated plasma IL-35 level on D1 was an independent indicator for predicting mortality with a hazard ratio of 1.189 (1.096-1.290). According to ROC curve, the AUROC of IL-35 is 0.855 (p <0.0001) and optimal cut-off point was 47.37pg/ml to predict mortality. In predicting MODS morbidity, the AUROC of IL-35 is 0.683 (p=0.0361) and optimal cut-off point was 46.98pg/ml. In addition, we also found that IL-35 positively correlated with APACHE II score and negatively correlated with the P/F ratio. During fist 7 days, nonsurvivors presented decreased trends of IL-35 based on higher background.