Application Of Novel Biomarkers YKL-40,CCL17 And NGAL In Children With Community-acquired Pneumonia

Objective:To explore the value of YKL-40,CCL17 and NGAL for early pathogen diagnosis and severity assessment in children with community-acquired pneumonia,and to compare with biomarkers commonly used in clinical practice.Methods:A total of 98 children diagnosed with CAP were selected from the pediatric respiratory department and hospitalized at the First Hospital of Jilin University between February 2022 and November 2022.The children were grouped based on clinical signs and symptoms,laboratory data,and imaging examinations.Based on the infection pathogen,the patients were divided into three groups: bacteria group(36 cases),virus group(17 cases),and mycoplasma pneumoniae group(45 cases).According to the severity of the disease,the patients were divided into two groups: mild group(77 cases)and severe group(21 cases).A control group of 23 healthy children who underwent physical examination at our hospital during the same period was also selected.YKL-40,CCL17,and NGAL levels in peripheral blood were detected using double antibody sandwich enzyme-linked immunosorbent assay.Additionally,WBC count,Neu%,CRP,PCT,and LDH levels in peripheral blood were detected.Statistical analysis was performed on the experimental data.Results:1.Compared to the control group,the levels of CCL17 and NGAL were significantly increased in the bacterial group(P < 0.05),but not in the viral or mycoplasma pneumoniae groups.The levels of CCL17 and NGAL were significantly increased in the mycoplasma pneumoniae group compared to the control and viral groups(P < 0.05).There were no significant differences in CCL17 and NGAL between the virus group and the control group(P > 0.05).There was no significant difference in YKL-40 between the bacterial,viral,mycoplasma pneumoniae,and control groups(P > 0.05).Compared to the viral and mycoplasma pneumoniae groups,WBC and CRP were significantly increased in the bacterial group(P < 0.05).Neu% was significantly increased in the bacterial and mycoplasma pneumoniae groups compared to the viral group(P < 0.05).There were no significant differences in PCT among the bacterial,viral,and mycoplasma pneumoniae groups(P > 0.05).LDH was significantly increased in the virus group compared to the mycoplasma pneumoniae group(P < 0.05),but there was no significant difference in LDH between the bacterial and mycoplasma pneumoniae groups(P > 0.05).2.Compared to the control group and mild group,the severe group showed a significant increase in CCL17 and NGAL levels(P < 0.05).The mild disease group also showed a significant increase in CCL17 and NGAL levels compared to the control group(P < 0.05).There was no significant difference in YKL-40 levels between the control group,mild group,and severe group(P > 0.05).WBC,Neu%,and CRP levels were significantly increased in the severe group compared to the mild group(P < 0.05).There were no significant differences in PCT and LDH levels between the mild and severe groups(P > 0.05).3.ROC curve analysis for diagnosing bacterial CAP in children showed that the areas under the curve of WBC,CRP,PCT,LDH,YKL-40,CCL17,and NGAL were 0.669,0.789,0.632,0.562,0.581,0.594,and 0.710,respectively.The optimum cut-off value of WBC was 11.44×10^9/L,and the sensitivity and specificity were 52.78% and 88.71%,respectively.The optimal cut-off value of CRP was 8.62mg/L,the sensitivity was 74.29%,and the specificity was 85.00%.The best truncation value of PCT was 0.26ng/m L,the sensitivity was 32.26%,and the specificity was 91.30%.The optimal cut-off value of LDH was 282U/L,the sensitivity was 63.89%,and the specificity was 55.17%.The best truncation value of YKL-40 was 110.12ng/m L,the sensitivity was 36.11%,and the specificity was 95.16%.The best truncation value of CCL17 was 631.66pg/m L,the sensitivity was 41.67%,and the specificity was 91.94%.The best truncation value of NGAL was 522.5ng/m L,the sensitivity was 50.00%,and the specificity was 88.71%.The sensitivity and specificity of PCT+CRP were 80.00% and 86.36%,respectively.The sensitivity and specificity of CRP+YKL-40 were 80.00% and 83.33%,respectively.The sensitivity and specificity of CRP+CCL17 were 88.57% and 73.33%,respectively.The sensitivity and specificity of CRP+NGAL were 77.14% and 86.67%,respectively.The sensitivity and specificity of PCT+YKL-40 were 48.39% and 89.13%,respectively.The sensitivity and specificity of PCT+CCL17 were 51.61% and 91.30%,respectively.The sensitivity and specificity of PCT+NGAL were 58.06% and 86.96%,respectively.4.Spearman’s test and Pearson’s test were used to analyze the correlation of biomarkers in different pathogen groups.WBC and NGAL in CAP of the bacteria group were positively correlated,and the correlation coefficient r was 0.348.LDH was positively correlated with NGAL,and the correlation coefficient r was 0.404(P < 0.05).CRP was negatively correlated with CCL17 in viral CAP,and the correlation coefficient r was 0.668.LDH was negatively correlated with YKL-40,and the correlation coefficient r was 0.709(P < 0.05).In the Mycoplasma pneumoniae group,LDH was negatively correlated with CCL17 and YLK-40,and the correlation coefficients r were 0.418 and 0.343,respectively(P < 0.05).Conclusions:1.The elevated levels of new biomarkers CCL17 and NGAL in children with pneumonia were consistent with the WBC count,Neu% and CRP trends in the blood of common biomarkers,and were positively correlated with the severity of pneumonia.2.The new biomarkers CCL17,NGAL and common biomarkers WBC count,Neu% and CRP in the bacterial group were significantly higher than those in the viral group and Mycoplasma pneumoniae group,indicating that the above biomarkers had certain predictive value for bacterial CAP.3.The combined detection of new and common biomarkers is of significant importance in improving the accuracy of diagnosing bacterial pathogens causing CAP in children.