Correlation Between The Expression Of NF-κB In Bronchoalveolar Lavage Fluid Of Severe Mycoplasma Pneumoniae Pneumonia In Children And Its Clinical Features And Cellular Immunity

BackgroundIn recent years,With the changes of epidemiological characteristics of common respiratory pathogens,Mycoplasma pneumoniae pneumonia(MPP)has been on the rise,as well as Severe Mycoplasma pneumoniae pneumonia(SMPP),Mycoplasma pneumo-niae(MP)infection can cause severe lung injury or multiple extrapulmonary organs,and even leave sequelae,which can be life-threatening in severe cases.However,the pathoge-nesis of MPP is still unclear.MP lipoproteins stimulate the excessive activation of Nuclear factor-κB(NF-κB)leading to immune inflammatory response,which may be involved in the pathogenic process of MP.Currently,there are only few reports about NF-κB in MPP bronchoalveolar lavage fluid(BALF)domestically and abroad.Therefore,the purpose of this study is to explore the level of NF-κB in bronchoalveolar lavage fluid of children with SMPP,the correlation between NF-κB and cellular immunity,and the relationship between NF-κB and disease severity and clinical characteristics.Objectives1.To study the correlation among NF-κB in BALF,intracellular NF-κB and total NF-κB in SMPP by detecting the level of NF-κB in the supernatant of BALF and intracellular;2.To study the correlation between NF-κB and MP-DNA,IL-6,CRP,cellular immune,fever,complications and hospitalization time.3.To observe the imaging and bronchoscopic changes of children with SMPP.4.To investigate the correlation between NF-κB in bronchoalveolar lavage fluid and cellular immunity and clinical features in children with SMPP.Methods41 children who underwent fiberoptic bronchoscopy and bronchoalveolar lavage and were finally diagnosed with SMPP from October 2021 to December 2021 in The First Clinical College of Xinxiang Medical University were selected as the SMPP group.And 13cases of Respiratory foreign body(FB)without infection during the same period were included in FB group.According to whether there were any extrapulmonary complications,the patients were divided into extrapulmonary complicated group and simple lung injury group;Pleural effusion group and non-pleural effusion group;Pericardial effusion group and non-pericardial effusion group;Multi-lobe lung injury group and single-lobe lung injury group;Atelectasis group and non-atelectasis group;mucus plug and no mucus plug group.The children underwent fiberoptic bronchoscopy and bronchoalveolar lavage within one week after admission,and the BALF was obtained as the experimental specimen,NF-κB in the supernatant of BALF after centrifugation(namely BALF NF-κB)and in BALF centrifugal sediment(the levels of total NF-κB in cytoplasm and nucleus,namely intracellular NF-κB)were detected by ELISA.Total NF-κB is the sum of BALF NF-κB and intracellular NF-κB.The correlation between NF-κB and laboratory examination results and clinical features in children with SMPP was analyzed,and the changes of chest imaging and bronchoscopy in children with SMPP were observed and statistically analyzed.Results1.The levels of BALF NF-κB,intracellular NF-κB and total NF-κB in SMPP group were significantly higher than those in FB group(P<0.001).The levels of these three NF-κB items were correlated with each other(P<0.01),suggesting that NF-κB was involved in the inflammatory airway changes in MPP,and the inflammation on the surface of inflammatory airway mucosa can reflect the inflammation of inflammatory airway.These three NF-κB were correlated with IL-6,mycoplasma load in BALF,heat peak and hospital stay(P<0.05),indicating that the higher NF-κB level,the higher MP-DNA,the higher IL-6,the higher thermal peak,and the longer hospital stay.The higher the intracellular NF-κB level in BALF,the lower the CD3~+CD4~+value in peripheral blood(P<0.05),There was no correlation with other immune cells(P>0.05).There was no correlation between the three NF-κB and age,WBC,LY,CRP,LDH(P>0.05).2.Intracellular NF-κB and total NF-κB were correlated with pleural effusion,pericardial effusion and extrapulmonary complications(P<0.05).BALF NF-κB,intracellular NF-κB and total NF-κB were all correlated with mucus plug(P<0.05).However,these three NF-κB items were not correlated with atelectasis and lung tissue damage(P>0.05).3.Mucosal changes under bronchoscopy,BALF NF-κB,intracellular NF-κB and total NF-κB were not correlated with mucosal folds,edema,pallor,hyperemic edema,hemorrhage or erosion(P>0.05).ConclusionNF-κB is involved in the occurrence and development of inflammatory airway in children with SMPP.The higher the NF-κB in airway,the higher the titer of MP-DNA in BALF and the IL-6 in peripheral blood,the lower the CD3~+CD4~+,the higher the thermal peak,the higher the incidence of sputum embolism,pleural effusion,pericardial effusion,and extrapulmonary complications,so as to the more serious the clinical manifestations,and the longer the hospitalization time.