Correlation of cytokine and cytology levels in bronchoalveolar alveolar lavage fluid of children with severe Mycoplasma pneumoniae pneumonia / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the clinical significance of cytokine levels and routine cytology in bronchoalveolar lavage fluid (BALF) in children with severe Mycoplasma pneumoniae pneumonia (SMPP).Methods:A total of 207 children with Mycoplasma pneumoniae pneumonia who underwent parallel bronchoalveolar lavage in the Department of Respiratory, Shanghai Children′s Hospital, Shanghai Jiaotong University from July 2018 to February 2019 were enrolled in this study.There were 121 patients in the SMPP group and 86 patients in the non-SMPP group.Flow cytometry was used to determine the level of cytokines in BALF.Meanwhile, the cells in BALF were stained and cytokines levels and routine cytology were compared between the 2 groups.Receive operating characteristic(ROC) curves were used to analyze the predictive value of cytokine levels and routine cytology for SMPP.Results:The levels of interleukin(IL)-8, IL-1βand IL-6 and white blood cell count in BALF of SMPP group were significantly higher than those of non-SMPP group [1 717.77 (784.31, 3 304.03) ng/L vs.1 013.03 (469.27, 2 040.52) ng/L, 373.18 (70.08, 941.56) ng/L vs.107.50 (0.10, 489.88) ng/L, 200.74 (41.09, 570.61) ng/L vs.95.47 (0.10, 337.68) ng/L, 1 890.00 (955.00, 3 600.00)×10 6/L vs.1 430.00 (467.50, 2 724.00)×10 6/L]( Z=3.27, 3.45, 2.47, 2.57, all P<0.05). The percentage of macrophages in the non-SMPP group was significantly higher than that in the SMPP group [0.04 (0, 0.12) vs. 0 (0, 0.06)] ( Z=-2.67, P=0.01). The optimal critical value and the area under curve (AUC) of IL-8 were 722.69 ng/L and 0.63 (95% CI 0.56-0.71, P<0.01), respectively. The optimal critical value and AUC of IL-1β were 166.33 ng/L and 0.64, respectively (95% CI 0.56-0.72, P<0.01). The optimal critical value and AUC of IL-6 were 142.95 ng/L and 0.60, respectively (95% CI 0.52-0.68, P<0.05). The optimal critical value and AUC of the total white blood cells were 970×10 6/L and 0.61, respectively (95% CI 0.53-0.69, P<0.05). The optimal critical value and AUC of the percentage of macrophages were 0.19 and 0.60, respectively (95% CI 0.32-0.48, P<0.05). Conclusions:Children with SMPP have higher levels of cytokines IL-8, IL-1β and IL-6, a higher white blood cell count, and a lower percentage of macrophages in BALF than children with no SMPP. However, cytokine levels and cytology are inadequate to predict SMPP since they are not effective in the clinical diagnosis of SMPP.