Changes in TLR4,IL-35,and CRP/ALB Levels and Their Impact on Severe Airway Responsiveness in Children with Bronchial Asthma Complicated by Mycoplasma Pneumoniae Infection

ZHAO Bin; XIE Lili; WANG Jingjing; ZHANG Chunling; PENG Jing; TIAN Ju; JIANG Zhong

doi:10.3639/j.issn.2095-3097.2026.02.019

Abstract：Objective To compare the changes in serum Toll-like receptor 4(TLR4),interleukin-35(IL-35),and C-reactive protein(CRP)/albumin(ALB)levels in children with bronchial asthma with or without Mycoplasma pneumoniae(MP)infection,and to analyze their impact on severe airway responsiveness.Methods A total of 140 children with bronchial asthma admitted to Qingdao Central Hospital of Rehabilitation University from May 2021 to December 2024 were retrospectively selected.All children underwent MP IgM antibody testing and were divided into two groups based on MP infection status:the MP-infected group(65 cases)and the non-MP-infected group(75 cases).The levels of TLR4,IL-35,and CRP/ALB were compared between the two groups.Children in the MP-infected group all underwent quantitative aerosol inhalation bronchial provocation testing using methacholine as the provoking agent.The cumulative dose of the provocant required to induce a 20%decrease in baseline forced expiratory volume in 1 second(PD20-FEV1)was used as the indicator of airway responsiveness.Spearman correlation analysis was used to analyze the correlations between serum TLR4,IL-35,CRP/ALB levels and airway responsiveness in asthmatic children with MP infection.Using PD20-FEV1<0.035 mg as the criterion for severe airway responsiveness,multivariate logistic regression analysis was performed to analyze the relationships between TLR4,IL-35,CRP/ALB levels and severe airway responsiveness.Results The levels of TLR4 and CRP/ALB in the MP-infected group were significantly higher than those in the non-MP-infected group,while the IL-35 level was significantly lower than that in the non-MP-infected group(P<0.001).Spearman correlation analysis showed that PD20-FEV1 was significantly negatively correlated with TLR4 and CRP/ALB levels,and significantly positively correlated with IL-35 level(r=-0.634,-0.592,0.516,respectively;P<0.001).Children with severe airway responsiveness had significantly higher TLR4 and CRP/ALB levels and significantly lower IL-35 levels compared to those with moderate airway responsiveness(P<0.001).Multivariate logistic regression analysis showed that TLR4 and CRP/ALB were independent risk factors for severe airway responsiveness in asthmatic children with MP infection,while IL-35 was an independent protective factor(OR=3.408,95%CI:1.526-7.611,P=0.003;OR=4.212,95%CI:1.491-11.903,P=0.007;OR=0.418,95%CI:0.197-0.886,P=0.023).Conclusion Serum TLR4,IL-35,and CRP/ALB levels in children with bronchial asthma and MP infection are significantly altered compared to those without MP infection.These indicators are correlated with airway responsiveness.High TLR4,high CRP/ALB,and low IL-35 levels influence severe airway responsiveness in children,and clinical further screening should be considered for children with these manifestations.