Correlation Between TLR2 And Cytokine Levels In Bronchoalveolar Lavage Fluid And Mycoplasma Pneumoniae Pneumonia In Children

Objective:To explore the role of TLR2 and downstream cytokines in children with Mycoplasma pneumoniae pneumonia（MPP）,and to investigate the correlation of disease severity,by detecting the levels of TLR2 and its downstream cytokines in the bronchoalveolar lavage fluid of children with MPP.Methods:According to the criteria of"Expert Consensus on Diagnosis and Treatment of Mycoplasma Pneumoniae Pneumonia in Children2015"^[14],105 children with pneumonia in the pediatric department of our hospital from September 2021 to September 2022 were enrolled and required bronchoscopy and bronchoalveolar lavage treatment.All the children were 2-10 years old.At the same time,the basic information and relevant clinical data including body temperature,pulse,blood pressure,respiratory rate,routine blood test,and treatment and prognosis data including time of antibiotic use,combined antibiotic use rate,frequency of oxygen inhalation/nebulization,hospitalization time,and hospitalization costs were completely collected.According to the etiological results,they were divided into MPP and non-MPP groups,and the MPP group was divided into general MPP and RMPP subgroups according to the severity of the disease.According to the results of etiology,children were divided into MPP group（66 cases）and Non MPP（NMPP）group（22 cases）.The MPP group was divided into the conventional MPP（38 cases）group according to the severity of the disease and the Refractory MPP（28 cases）group.The bronchoalveolar lavage specimens of all children were prefabricated and prepared immediately after the operation.The levels of TLR2 receptor and downstream cytokines including IL-6,IL-10,and TNF-αwere detected by double-antibody sandwich ELISA.SPSS 25.0 statistical software was used for statistical analysis.All data were tested by K-S method for normal distribution,the normally distributed data were expressed as mean±standard deviation（（?）±S）,one-way ANOVA was used for comparison between multiple groups,and LSD test was used for pairwise comparison between groups.The counting data was represented by n（%）and was analyzed byc²test,and bivariate data were analyzed by linear correlation.he predictive value of disease severity was assessed using the area under the receiver Operating Characteristic（ROC）curve（AUC）.P<0.05indicated a statistically significant difference.Results:（1）The levels of TLR2,IL-6,IL-10 and TNF-αin alveolar lavage fluid in MPP and RMPP groups were significantly higher than those in NMPP group,and the difference was statistically significant（P﹤0.05）.The levels of TLR2 and related cytokines in RMPP group were significantly higher than those in MPP group（78.18±8.38 vs.45.42±10.39,61.32±11.00 vs.34.05±5.87,65.18±11.95 vs.34.16±6.19,respectively）.123.18±11.09 vs.92.92±7.75),the differences were statistically significant（P﹤0.05）.（2）TLR2 level was significantly correlated with MPP severity（rs=0.833,P>0.05）.TLR2 levels were positively correlated with IL-6,IL-10 and TNF-α（r=0.843,0.867,0.845,P﹤0.05）.The area under ROC curve of TLR2 horizontal diagnosis of MPP was 0.987,with statistical significance（P﹤0.05）,the cut off value was 33.5 pg/m L,sensitivity was 97%,specificity was 100%.Conclusion:The high expression of TLR2 and its mediated release of inflammatory cytokines is one of the important pathogenesis of MPP in children.The level of TLR2 protein in alveolar lavage fluid is of high clinical value for the diagnosis of MPP,and its high level is closely related to the disease.