Abstract: Objective To explore the expression and significance of Clara cell secretory protein 16 (CC-16),pulmonary surfactant protein A (SP-A), N-terminal pro-B type natriuretic peptide(NT-proBNP) and interleukin-17 (IL-17) in neonatal respiratory distress syndrome (NRDS). 
 Methods In total, 98 children with NRDS admitted to Hanchuan People′s Hospital of Hubei Province from January 2021 to February 2023 were included in the NRDS group, including 38 mild cases, 33 moderate cases and 27 severe cases. In addition, another 50 healthy newborns born in our hospital during the same period were included in the healthy group. The levels of CC-16, SP-A, NT-proBNP and IL-17 were compared between the two groups. Receiver operating characteristic (ROC) curve was used to analyze the value of CC-16, SP-A, NT-proBNP, and IL-17 alone and in combination in evaluating NRDS. The baseline data and levels of CC-16, SP-A, NT-proBNP and IL-17 in NRDS children with different severity were compared. Spearman rank correlation analysis was used to examine the correlation between CC-16, SP-A, NT-proBNP, IL-17 levels and the severity of NRDS. 
 Results The levels of CC-16, SP-A, NT-proBNP and IL-17 in NRDS group ［(60.21±3.85) mg/L, (74.96±6.35) mg/L, (5 063.44±992.65) ng/L, (99.75±30.42) ng/L］ were significantly higher than those in the healthy group ［(12.09±1.27) mg/L, (17.88±2.76) mg/L, (1 872.49±502.51) ng/L, (58.82±15.73) ng/L］, with significant difference (P＜0.05). The results of ROC curve analysis showed that the area under the ROC curve (AUC) of CC-16, SP-A, NT-proBNP and IL-17 for evaluating NRDS was 0.845, 0.870, 0.846 and 0.885, respectively; the AUC of the combination of the above indicators for evaluating NRDS was 0.927, and the sensitivity was 0.980. The levels of CC-16, SP-A, NT-proBNP and IL-17 in mild group ［(37.69±10.52) mg/L, (46.85±7.36) mg/L, (3 472.57±295.14) ng/L, (39.86±12.45) ng/L］ were lower than those in moderate group ［(52.37±16.24) mg/L, (72.81±8.06) mg/L, (4 886.29±334.72) ng/L, (101.49±32.13) ng/L］ and severe group ［(85.13±14.44) mg/L, (97.23±12.37) mg/L, (6 379.36±362.47) ng/L, (146.52±35.08) ng/L］, and the levels of CC-16, SP-A, NT-proBNP and IL-17 in moderate group were lower than those in severe group, with significant difference (P＜0.05). CC-16, SP-A, NT-proBNP, and IL-17 were positively correlated with the severity of NRDS (r=0.549, 0.574, 0.607, 0.563,  all P＜0.05). 
 Conclusion The expression levels of CC-16, SP-A, NT-proBNP and IL-17 in NRDS are increased, which can be used for the diagnosis of NRDS, and the sensitivity of combined diagnosis is higher. The above indicators are positively correlated with the severity of NRDS. 

Key words: respiratory distress syndrome, newborn, CC-16, SP-A, NT-proBNP, IL-17 ,