The Role And Clinical Significance Of Mir-487b And IL-33 In The Pathogenesis Of Refractory Mycoplasma Pneumoniae Pneumonia In Chidren

Objective: The aim of this study was to investigate the relationship between the expression levels of miR-487b,IL-33 and IL-6 in plasm and bronchoalveolar lavage fluid(BALF)of children with refractory Mycoplasma pneumonia pneumonia(RMPP)and common Mycoplasma pneumoniae pneumonia(GMPP).The correlation analysis of miR-487b,IL-33 and IL-6 in the pathogenesis of children with MPP was performed by comparing the clinical date and laboratory indicators of RMPP and GMPP.Methods: Children with Mycoplasma pneumoniae pneumonia who were hospitalized in the Pediatrics Department of our hospital from September 2019 to December 2021 were selected.The experimental group was divided into RMPP group and GMPP group,30 cases in each group.According to the needs of the disease,electronic bronchoscopy and bronchoalveolar lavage were performed in the acute phase.The RMPP group underwent second bronchoscopy and bronchoalveolar lavage in the recovery phase of the disease.Venous blood was collected in both group during the acute phase and the recovery phase.Twenty children who underwent bronchoscopy for foreign body removal during the same period were selected as the control group,and the venous blood was collected in the acute phase of the control group.The expression levels of miR-487b in plasma and BALF were detected by real-time quantitative PCR(RT-PCR),and the expression levels of IL-33 and IL-6 in plasma and BALF were detected by enzyme-linked immunosorbent assay(ELISA).Clinical date and laboratory indicators of children,including: admission days,fever days,white blood cell count,neutrophil count,platelets,C-reactive protein(CRP),lactate dehydrogenase(LDH),creatine kinase isoenzyme(CK-MB),pleural effusion,and lung consolidation,and statistical analysis was performed.Results:1.The expression levels of miR-487b in phasma and BALF in the acute phase of the RMPP group were significantly lower than those in the recovery phase,while the expression levels of IL-33 and IL-6 were significantly higher than those in the recovery phase;the expression of miR-487b in the acute phase plasma of the GMPP group,the level was significantly lower than the recovery period,while the expression levels of IL-33 and IL-6 were significantly higher than the recovery period,the differences were statistically significant(P <0.05).2.The expression levels of miR-487b in phasma and BALF in the acute phase of the RMPP group were significantly lower than those of the GMPP group in the acute phase and control group,while the expression levels of IL-33 and IL-6 were significantly higher than those in the GMPP group in the acute phase and the control group;The expression levels of miR-487b in the acute phase plasma and BALF of the GMPP group were significantly lower than those of the control group,while the expression levels of IL-33 and IL-6 were significantly higher than those of the control group,with statistical significance(P <0.05).3.The expression levels of miR-487b in phasma and BALF in the acute phase of the RMPP group were significantly positively correlated(r=0.826,P<0.05),and the expression levels of IL-33 in plasma and BALF were significantly positive correlated(r=0.944,P<0.05);The expression levels of miR-487b in acute phase plasma and BALF in the acute phase of the GMPP group were significantly positively correlated(r=0.890,P<0.05),and the correlation analysis of the expression levels of IL-33 in plasma and BALF showed a significant positive correlation(r=0.924,P<0.05).4.The expression levels of miR-487b and IL-33 in the acute phase phasma and BALF in RMPP group were significantly negatively correlated(plasma: r=-0.899,P<0.05;BLAF: r=-0.924,P<0.05),while there was no correlation between miR-487b and IL-6 expression level in plasma,miR-487b in BLAF was negatively correlated with IL-6 expression level(r=-0.784,P<0.05),and IL-33 and IL-6 expression levels were significantly positive correlation(plasma: r=0.910,P<0.05;BALF: r=0.932,P<0.05);The expression levels of miR-487b and IL-33 in acute phase plasma and BALF of GMPP group were significantly negatively correlated(plasma: r=-0.795,P<0.05;BALF: r=-0.935,P<0.05),and the expression levels of IL-6 was negatively correlated(plasma: r=-0.718,P<0.05;BALF: r=-0.871,P<0.05),and the expression levels of IL-33 and IL-6 were significantly positively correlated(plasma: r=0.837,P<0.05;BALF: r=0.956,P<0.05).5.Comparing the clinical date and laboratory indexes between the RMPP group and the GMPP group,there were statistically significant differences in hospital admission days,fever days,lactate dehydrogenase(LDH),C-reactive protein(CRP),pleural effusion,and lung consolidation(P<0.05),and the hospital admission days,fever days,LDH,CRP,pleural effusion,and lung consolidation in the RMPP group were significantly higher than those in the GMPP group,There was no significant difference in WBC,NEUT,PLT,CK-MB indexed.6.Binary Logistic regression analysis of the variables with statistical significance in the occurrence of RMPP showed that miR-487b was an independent protective factor in children with RMPP,and IL-33,IL-6,CRP and LDH were independent risk factors.7.The ROC curve was drawn with the expression levels of miR-487b and IL-33 as variables.According to the principle of maximum Youden index,the optimal cut-off value of miR-487b in the diagnosing RMPP was 0.389,the sensitivity was 100%,and the specificity was 56.7%;the best cut-off value of IL-33 for diagnosing RMPP was607.742,the sensitivity was 60%,and the specificity was 86.7%.Conclusion: 1.miR-487b may be involed in the pathogenesis of RMPP by regulating the expression of IL-33 to regulate the secretion of the downstream cytokine IL-6.miR-487b may be an independent protective factor of RMPP.IL-33,IL-6,CRP and LDH may be independent risk factors for RMPP;2.It is speculated that miR-487b and IL-33 may be indicators for predicting RMPP and provide new biological markers for clinical diagnosis and treatment of RMPP.