Significance of neutrophil extracellular trap and its markers in the early diagnosis of community-acquired pneumonia in children / 中国当代儿科杂志

OBJECTIVE@#To study the significance of plasma neutrophil extracellular trap (NET) and its markers in the diagnosis of community-acquired pneumonia (CAP) in children.@*METHODS@#A total of 160 children with CAP were enrolled as the CAP group, and 50 healthy children were enrolled the control group. According to disease severity, the CAP group was further divided into a mild CAP subgroup with 137 children and a severe CAP subgroup with 23 children. According to the pathogen, the CAP group was further divided into a bacterial pneumonia subgroup with 78 children, a Mycoplasma pneumonia subgroup with 35 children, and a viral pneumonia subgroup with 47 children. The levels of plasma NET and its markers [antibacterial peptide (LL-37), extracellular free DNA (cfDNA), and deoxyribonuclease I (DNase I)] were measured. Receiver operating characteristic (ROC) curve was used to analyze the value of each index in diagnosing CAP and assessing its severity.@*RESULTS@#Compared with the control group, the CAP group had significant increases in the levels of NET, LL-37, and cfDNA and a significant reduction in the activity of DNase I (P0.05). In the CAP group, plasma NET levels were positively correlated with white blood cell count (WBC), percentage of neutrophils, and serum levels of C-reactive protein (CRP), procalcitonin and tumor necrosis factor-α (r=0.166, 0.168, 0.275, 0.181 and 0.173 respectively, P<0.05); LL-37 and cfDNA levels were positively correlated with WBC (r=0.186 and 0.338 respectively, P<0.05) and CRP levels (r=0.309 and 0.274 respectively, P<0.05); the activity of DNase I was negatively correlated with CRP levels (r=-0.482, P<0.05). The ROC curve analysis showed that NET, LL-37, cfDNA, and DNase I had an area under the ROC curve (AUC) of 0.844, 0.648, 0.727, and 0.913 respectively in the diagnosis of CAP, with optimal cut-off values of 182.89, 46.26 ng/mL, 233.13 ng/mL, and 0.39 U/mL respectively, sensitivities of 88.12%, 35.63%, 54.37%, and 91.25% respectively, and specificities of 74.00%, 92.00%, 86.00%, and 76.00% respectively. In the assessment of the severity of CAP, NET, LL-37, cfDNA, and DNase I had an AUC of 0.873, 0.924, 0.820, and 0.778 respectively, with optimal cut-off values of 257.7, 49.11 ng/mL, 252.54 ng/mL, and 0.29 U/mL respectively, sensitivities of 83.21%, 86.96%, 78.26%, and 95.65% respectively, and specificities of 78.26%, 83.94%, 76.64%, and 56.93% respectively.@*CONCLUSIONS@#Plasma NET and its related markers have a certain value in diagnosing CAP and assessing its severity in children.

Value of simultaneous amplification and testing in early diagnosis of Mycoplasma pneumoniae pneumonia and related influencing factors / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the value of simultaneous amplification and testing (SAT) in the early diagnosis of Mycoplasma pneumoniae pneumonia (MPP) in children and related influencing factors.</p><p><b>METHODS</b>A total of 526 children with community-acquired pneumonia who were hospitalized between December 2016 and December 2017 were enrolled. Particle agglutination was used to measure serum Mycoplasma pneumoniae (MP) antibody (MP-Ab). The value of SAT in the diagnosis of MPP was evaluated based on these results.</p><p><b>RESULTS</b>Based on the results of serum MP-Ab measurement, 165 children were diagnosed with MPP. MP-SAT had a sensitivity of 90.9% (150/165), a specificity of 97.9% (368/376), and high accuracy (Youden index=0.89) in the diagnosis of MPP, suggesting that there was good consistency between these two methods (Kappa=0.90). The diagnostic sensitivity of MP-SAT in children with a short course of disease was significantly higher than that in children with a long course of disease (P=0.031). The diagnostic sensitivity of MP-SAT was significantly higher than that of single serum MP-Ab measurement (P=0.018), with poor consistency between these two methods (Kappa=0.039). MP-SAT had good consistency with double serum MP-Ab measurement (Kappa=0.91). The multivariate logistic regression analysis showed that course of disease (≥7 days) and out-of-hospital macrolide treatment were the main factors influencing the results of MP-SAT (P<0.05).</p><p><b>CONCLUSIONS</b>MP-SAT has high value in the early diagnosis of MPP and can effectively cover the shortage of single serum MP-Ab test in the acute stage and thus provide help for early clinical diagnosis. MP-SAT test should be performed in the early stage of the disease (<7 days) and before the application of macrolide treatment.</p>