The predictive values of soluble B7-DC in children with refractory mycoplasma pneumoniae pneumonia

BACKGROUND: Refractory mycoplasma pneumoniae pneumonia (RMPP) is a serious mycoplasma pneumoniae infection and is difficult to diagnose early. The levels of serum soluble B7-dendritic cell (sB7-DC) in children with mycoplasma pneumoniae pneumonia (MPP) were assessed to explore the clinical significance of sB7-DC levels in RMPP. METHODS: A total of 65 patients with mycoplasma pneumoniae pneumonia (MPP) were enrolled in this study between January 2017 and December 2018. The patients were divided into the general mycoplasma pneumoniae pneumonia (GMPP) (n=30) and RMPP groups (n=35); the data of 20 normal children served as a control group (n=20). An enzyme-linked immunoassay kit was used to detect the expression of soluble B7-dendritic cell (sB7-DC) and other inflammatory factors. Binary logistic regression was performed to identify the independent predictors of RMPP. Receiver operating characteristic (ROC) curves were drawn to evaluate the value of each independent risk factor in the early diagnosis of RMPP. RESULTS: The results showed that compared to the GMPP group, children in the RMPP group had a significantly longer hospital stay and had a significantly longer fever duration (P<0.05). The values of interferon-gamma (IFN-γ), interleukin 17 (IL-17), and sB7-DC in the RMPP group were significantly higher than those in the normal control and GMPP groups (all P<0.05). The results of the correlation analysis showed that sB7-DC was positively correlated with IFN-γ and IL-17 and these indicators could be used in combination to evaluate the severity of the disease. The binary logistic regression analysis identified IL-17 and sB7-DC as independent risk factors for RMPP (P<0.05). The ROC curve analysis showed that the cut-off values of IL-17 and sB7-DC were 309.6 pg/L and 1,109.7 pg/mL, respectively. The areas under the curve (AUCs) of IL-17 and sB7-DC were 0.741 and 0.794, respectively. The sensitivity of IL-17 to RMPP prediction was 83.3%, and the specificity was 62.9%. The sensitivity and specificity of sB7-DC to RMPP were 86.7% and 62.9%, indicating that sB7-DC had the highest predictive power for RMPP. CONCLUSIONS: The level of serum sB7-DC may play an important role in the early diagnosis of RMPP. Our research results provide a theoretical basis for the early diagnosis of RMPP.