PADI4 and alkaline phosphatase measurement: In this study, we found that (1) circulating CitH3 was increased dramatically in septic AP but not in sterile AP or healthy subjects; (2) concentration of CitH3 was positively correlated with PAD2/PAD4 expression and serum dsDNA concentration; (3) serum levels of CitH3 correlated positively with disease severity and clinical outcomes.