OBJECTIVE To observe the levels of serum soluble triggering receptor expressed on myeloid cells (sTREM-1), matrix metalloproteinase-9 (MMP-9), α1-antitrypsin(α1-AT) and 25 hydroxyvitamin D3 25(OH)D3 in the neonates with infectious pneumonia and analyze the association with the types of infectious pneumonia.

METHODS A total of 109 neonates with infectious pneumonia who were treated in Jianyang People′s Hospital from Jan 2021 to Dec 2022 were assigned as the infection group, meanwhile 115 healthy neonates who were born in the hospital were chosen as the non-infection group.The levels of serum sTREM-1, MMP-9, α1-AT and 25(OH)D3 were compared between the two groups.The neonates of the infection group were divided into the bacterial infection group with 65 cases and the non-bacterial infection group with 44 cases according to the types of infectious pneumonia.The values of serum sTREM-1, MMP-9, α1-AT and 25(OH)D3 in differential diagnosis of types of infectious pneumonia were analyzed by means of receiver operating characteristic (ROC) curves.

RESULTS The levels of serum sTREM-1, MMP-9 and α1-AT of the infection group were higher than those of the non-infection group(P < 0.05), while the serum 25(OH)D3 level of the infection group was lower than that of the non-infection group(P < 0.05).The levels of serum sTREM-1, MMP-9 and α1-AT of the bacterial infection group were higher than those of the non-bacterial infection group(P < 0.05), while the serum 25(OH)D3 level of the infection group was lower than that of the non-bacterial infection group(P < 0.05).The area under curve (AUC) of the joint detection of the four indexes was 0.866 in differential diagnosis of the types of infectious pneumonia, with the sensitivity 81.54%, the specificity 77.27%.

CONCLUSION The infectious pneumonia may lead to the changes of serum sTREM-1, MMP-9, α1-AT and 25(OH)D3 level of the neonates.The four indexes have significant value in differential diagnosis of the types of infectious pneumonia.