目的 探讨支气管肺泡灌洗液（BALF）YKL-40与肺炎支原体肺炎（MPP）患儿气道损害之间的相关性。方法 选取60例MPP患儿为MPP组，12例支气管异物患儿作为对照组。根据影像学表现将MPP组分为3个亚组：斑片状影（n=34）、肺实变（n=19）、毛玻璃样变（n=7）；根据支气管镜下表现分为3个亚组：黏膜充血水肿（n=38）、黏液性分泌物（n=18）、塑型性支气管炎（n=4）。分析MPP患儿的临床表现、实验室检查特点，检测MPP患儿BALF的YKL-40表达水平。结果 MPP组血清乳酸脱氢酶、BALF YKL-40水平高于对照组（P < 0.05）。肺实变亚组血清C-反应蛋白及乳酸脱氢酶水平高于斑片状影亚组（P < 0.05），肺实变亚组和毛玻璃样变亚组BALF YKL-40高于斑片状影亚组（P < 0.05）；塑型性支气管炎亚组BALF YKL-40均高于黏膜充血水肿亚组、黏液性分泌物亚组（P < 0.05）；黏液性分泌物亚组、塑型性支气管炎亚组气促比例高于黏膜充血水肿亚组（P < 0.05）；塑型性支气管炎亚组血清C-反应蛋白、乳酸脱氢酶水平高于黏膜充血水肿亚组（P < 0.05）。结论 BALF YKL-40与MPP患儿气道损害相关，且与疾病严重程度有关。

Objective To investigate the association of YKL-40 in bronchoalveolar lavage fluid (BALF) with airway damage in children with Mycoplasma pneumoniae pneumonia (MPP). Methods A total of 60 children with MPP who were admitted to the hospital were enrolled as the MPP group, and 12 children with bronchial foreign bodies were enrolled as the control group. According to the imaging findings, the MPP group was further divided into 3 subgroups:pulmonary patchy shadow (n=34), pulmonary consolidation (n=19) and pulmonary ground-glass opacity (n=7). According to the bronchoscopic findings, the MPP group was further divided into 3 subgroups:mucosal congestion/edema (n=38), mucous secretion (n=18) and plastic bronchitis (n=4). The clinical manifestations and laboratory characteristics of the children with MPP were analyzed, the expression of YKL-40 in BALF was measured. Results The MPP group had significantly higher levels of serum lactate dehydrogenase and BALF YKL-40 than the control group (P < 0.05). The pulmonary consolidation subgroup had significantly higher levels of serum C-reactive protein and lactate dehydrogenase than the pulmonary patchy shadow subgroup (P < 0.05), and the pulmonary consolidation and pulmonary ground-glass opacity subgroups had a significantly higher level of BALF YKL-40 than the pulmonary patchy shadow subgroup (P < 0.05). The plastic bronchitis subgroup had a significantly higher level of BALF YKL-40 than the mucous secretion and mucosal congestion/edema subgroups (P < 0.05). The mucous secretion and plastic bronchitis subgroups had a significantly higher proportion of children with shortness of breath than the mucosal congestion/edema subgroup (P < 0.05). The plastic bronchitis subgroup had significantly higher serum levels of C-reactive protein and lactate dehydrogenase than the mucosal congestion/edema subgroup (P < 0.05). Conclusions The level of BALF YKL-40 is associated with airway damage and disease severity in children with MPP.