Objective To investigate the expression and antibacterial function of Neutrophil extracellular traps (NETs) in systemic lupus erythematosus (SLE) patients.Methods Thirty stable SLE patients and thirty normal controls (NC) were recruited to this study.The acitivity of SLE was assessed by SLE Disease Activity Index (SLEDAI).Density gradient centrifugation was uesd to isolate neutrophilic granulocytes.Picogreen assay was used to quantify NETs formation.Colony counting method was used to compare the antibacterial rate of NETs between two groups.Variation of quantity and activities of neutrophil elastase (NE) and myeloperoxidase (MPO) on induced NETs was tested by enzyme linked immunosorbent assay (ELISA).Results There was no significant difference in the number of NETs between SLE and NC.Compared to the control group,more NETs were induced from neutrophils in SLE,the antibacterial rate of induced NETs was significantly lower,with the activities of antibacterial protein MPO decreased.Conclusions Stable SLE patients are more easily to induce NETs,and the antibacterial function of induced NETs are truly defective,may be related to the decreased activity of the antibacterial protein MPO.