MPO and Sepsis: PADI4 and MPO contribute to the formation of NETosis: PADI4 facilitates chromatin decondensation by catalyzing histone arginine deimination, thereby promoting NET formation (44), while MPO, an enzyme produced by neutrophils and an essential component of the innate immune system, plays a role in microbial killing and has potential as a biomarker for distinguishing sepsis from non-infectious systemic inflammation (45).