[Characteristics and clinical significance of neutrophil extracellular traps in children with inflammatory bowel disease].

To evaluate the characteristics of neutrophil extracellular traps (NET) in children with inflammatory bowel disease (IBD) and its role in diagnosis and disease activity monitoring. A total of 66 IBD children admitted to Beijing Children's Hospital from December 2017 to August 2024 were enrolled in this cross-sectional study, another 20 age-matched children who underwent gastrointestinal endoscopy during the same period in the same hospital and showed no abnormalities were selected as the controls. Clinical data of IBD and control group were collected. Children with IBD were divided into active group and remission group according to clinical score and endoscopic score. The peripheral blood of IBD and control group were collected, and the levels of NET markers, including neutrophil elastase (NE) and myeloperoxidase (MPO)-DNA were detected by enzyme-linked immunosorbent assay. The levels of NET markers in control group and different IBD groups were compared. Independent sample -test or Mann-Whitney test was used for group comparisons. Kruskal-Wallis test was used for multiple group comparisons. Spearman correlation analysis was used to analyze the correlation between NET markers and IBD activity. The efficacy of laboratory indicators in diagnosing IBD and control group was evaluated using receiver operating characteristic (ROC) curve. There were 66 children with IBD, including 36 in Crohn's disease group with the age of (11.0±3.7) years, and 30 in ulcerative colitis (UC) group with the age of (8.3±5.0) years. The control group consisted of 20 children with the age of (10.1±3.5) years. Compared with control group, the levels of NE (958 (771, 1 328) 303 (196, 501) μg/L) and MPO-DNA (0.11 (0.09, 0.18) 0.09 (0.06, 0.12)) in peripheral blood of IBD group were significantly higher (both <0.05). However, there was no significant difference in the levels of NE (1 008 (863, 1 301) 807 (567, 1 535) μg/L) and MPO-DNA (0.11 (0.09, 0.21) 0.12 (0.09, 0.14)) between Crohn's disease and UC groups (both >0.05). The NE levels in the endoscopic active group and remission group of Crohn's disease were higher than those in the control group (both <0.05). The MPO-DNA level in the endoscopic active group of Crohn's disease was higher than that in the control group (<0.05), while the MPO-DNA level in the endoscopic remission group of Crohn's disease was lower than that in the control group (>0.05). The NE levels in the endoscopic activity group and remission group of UC were higher than those in control group (both <0.05). NET markers were not correlated with the clinical activity and endoscopic activity of IBD (all >0.05). ROC curve analysis showed that the area under the curve of NE combined with MPO-DNA for distinguishing IBD from controls was 0.95, with a sensitivity was 90.0% and a specificity was 89.4%. The combination of NE and MPO-DNA demonstrated high sensitivity and specificity for distinguishing pediatric IBD patients from healthy children, suggesting its potential as a diagnostic biomarker panel of IBD.