The predictive value of LAYN,MUC5AC and MUC5B levels in bronchoalveolar lavage fluid for refractory mycoplas-ma pneumoniae pneumonia complicated with plastic bronchitis in children

Duan Linlin; Liu Yanan; Li Huafeng; Wang Junqi; Zhu Jiangchuan

doi:10.3969/j.issn.1671-6450.2025.08.015

Abstract：Objective To investigate the predictive value of bronchoalveolar lavage fluid Layilin(LAYN),mucin 5AC(MUC5AC)and mucin 5B(MUC5B)levels in children with refractory Mycoplasma pneumoniae pneumonia(RMPP)complicated with plastic bronchitis(PB).Methods A total of 127 children with RMPP(RMPP group)and 71 healthy children(healthy control group)admitted to the Department of Pediatrics,Linfen People's Hospital from April 2022 to April 2024 were selected as the observation objects.According to whether they were complicated with PB,the children with RMPP were divided into PB subgroup(44 cases)and non-PB subgroup(83 cases).The levels of LAYN,MUC5 AC and MUC5 B in bron-choalveolar lavage fluid were detected.The correlation between LAYN,MUC5 AC,MUC5 B and clinical parameters of chil-dren with RMPP was analyzed by Pearson or Spearman.Multivariate Logistic regression analysis was used to analyze the fac-tors of PB in children with RMPP.Receiver operating characteristic(ROC)analysis was used to analyze the value of LAYN,MUC5 AC and MUC5 B in the diagnosis of PB in children with RMPP.Results The levels of LAYN,MUC5 AC and MUC5 B in bronchoalveolar lavage fluid in RMPP group were higher than those in healthy control group(t/P=16.747/＜0.001,10.386/＜0.001,13.484/＜0.001),and those in PB subgroup were higher than those in non-PB subgroup(t/P=7.657/＜0.001,9.355/＜0.001,12.503/＜0.001);The levels of LAYN,MUC5 AC and MUC5 B were positively correlated with peak body tem-perature,fever time,hospitalization time,C-reactive protein(CRP),lactate dehydrogenase(LDH),neutrophil count,procalcito-nin(PCT)and interleukin-6(IL-6)(r/P=0.536/＜0.001,0.489/＜0.001,0.396/0.002,0.236/0.019,0.353/0.007,0.653/＜0.001,0.493/＜0.001,0.311/0.010;0.516/＜0.001,0.472/＜0.001,0.389/0.004,0.228/0.021,0.368/0.006,0.603/＜0.001,0.473/0.000,0.383/0.005;0.553/＜0.001,0.469/＜0.001,0.352/0.008,0.251/0.015,0.309/0.009,0.618/＜0.001,0.438/＜0.001,0.329/0.009).High peak body tem-perature,high neutrophil count,atelectasis,high level of LAYN,high level of MUC5 AC and high level of MUC5 B were risk factors for PB in children with RMPP[OR(95％CI)=3.865(1.714-8.718),2.593(1.219-5.516),1.958(1.044-3.674),1.705(1.018-2.856),1.827(1.019-3.277),1.643(1.005-2.688)];the area under the curve of LAYN,MUC5 AC,MUC5 B and the three in the diagnosis of PB in children with RMPP was 0.771,0.841,0.797 and 0.941,respectively.The diagnosis of the three was higher than that of the single diagnosis(Z/P=3.687/＜0.001,2.485/0.001,3.093/＜0.001).Conclusion The increased levels of LAYN,MUC5 AC and MUC5 B in bronchoalveolar lavage fluid of children with RMPP are related to PB,and the combi-nation of the three has high value in PB risk assessment.