To investigate the correlation between the levels of cell-free DNA (cfDNA), a marker of neutrophils extracellular traps (NETs), and platelet activation.

According to inclusion criteria and exclusion criteria, 51 patients were divided into sepsis group (29 cases) and control group (22 cases). Concentrations of cfDNA, PF4 and P-selectin in peripheral plasma were detected by ELISA. SPSS 25.0 was used for statistical analysis. The biochemical indicators, cfDNA and platelet markers (PF4, P-selectin), acute physiology and chronic health evaluation II score (APACHE II score), sequential organ failure score (SOFA), International Society on Thrombosis and Haemostasis (ISTH) score for DIC within 24 hours of ICU admission were compared between the groups. The correlation analysis was performed between cfDNA and platelets count, platelet markers (PF4, P-selectin), inflammatory markers (neutrophil count, CRP, PCT), coagulation test (PT, APTT, D-dimer, ATⅢ), disease severity (APACHEⅡ, SOFA score, ISTH score, JAAM score) in the sepsis group.

The level of cfDNA was significant elevated in sepsis group (174.499±76.596 vs 114.354±19.319, P＜0.05), but no significant statistical difference was found in levels of P-selectin and PF4. There were correlation between cfDNA and the P-selectin/PLT, D-dimer, C-reactive protein, APACHE Ⅱ, and JAAM in sepsis group (P＜0.05). However, it was not significantly correlated with neutrophil count, platelet count, platelet markers (PF4, P-selectin) or ISTH score (P＞0.05).

cfDNA in the sepsis group is significantly elevated. There is a significant positive correlation between cfDNA and D-dimer in the sepsis group, which suggests that NETs may be closely related to the secondary fibrinolysis process. Although there is a positive correlation between cfDNA and P-selectin / PLT in the sepsis group, because P-selectin is not a specific platelet activation marker, the relationship between NETs and sepsis platelet activation may be insufficient.