人副流感病毒相关下呼吸道感染患儿支气管肺泡灌洗液T细胞活化增强的临床意义

Clinical significance of enhanced T cell activation in bronchoalveolar lavage fluid in children with human parainfluenza virus-associated lower respiratory tract infection

目的:探讨人副流感病毒(HPIV)相关下呼吸道感染(LRTIs)患儿的支气管肺泡灌洗液(BALF)中各种细胞因子以及T细胞活化在急性期和恢复期的变化及临床意义。方法:选取37例LRTIs儿童作为研究对象,采集患儿急性期和恢复期BALF样本。根据严重程度指数(IOS)评估患儿急性期时疾病严重程度,将患儿分为轻度、中度和重度。采用多重实时荧光聚合酶链反应(PCR)分析BALF样本中HPIV基因型(1~4)。采用流式细胞术分析BALF样本中T细胞亚群(CD3^(+)、CD69^(+)、CD25^(+)和HLA-DR^(+))。采用酶联免疫吸附法检测BALF样本中白细胞介素(IL)-6、IL-10、IL-2、肿瘤坏死因子-α(TNF-α)、干扰素-γ(IFN-γ)、转化生长因子-β(TGF-β)。结果:HPIV-3基因型的检出率最高,为83.78%(31/37)。急性期样本中全血白细胞计数、中性粒细胞计数和淋巴细胞计数较恢复期升高,但血红蛋白水平和红细胞计数降低(P<0.05);与恢复期相比,急性期BALF样本中CD3^(+)T细胞计数降低,但是CD69^(+)、CD25^(+)、HLA-DR^(+)T细胞计数增多,同时CD4^(+)/CD8^(+)值升高(P<0.05)。急性期BALF样本中IL-6、IL-2、TNF-α、IFN-γ水平高于恢复期(P<0.05)。急性期BALF样本中度组和重度组的CD69^(+)T细胞计数、CD4^(+)/CD8^(+)值及IL-10、IL-2、IFN-γ水平均高于轻度组,CD3^(+)T细胞计数低于轻度组;重度组CD69^(+)T细胞计数、CD4^(+)/CD8^(+)值及IL-10、IL-2、IFN-γ水平较中度组进一步升高,CD3^(+)T细胞计数较中度组进一步降低(P<0.05)。结论:活化的T细胞在HIPVs感染的发病机制中起着重要作用,这可能是确定儿童病毒感染的重要免疫学和临床监测工具。

Objective:To investigate the changes and clinical significance of various cytokines and T cell activation in bronchoalveolar lavage fluid(BALF)of children with human parainfluenza virus(HPIV)associated lower respiratory tract infection(LRTIs)during acute and convalescence stages.Methods:Thirty-seven children with LRTIs were selected as the research subjects,and BALF samples at acute phase and recovery phase were collected.According to the index of severity(IOS),the severity of the disease during the acute phase was assessed as mild,moderate and severe.HPIV genotypes(1-4)were analyzed by multiple quantitative real-time polymerase chain reaction(PCR)in BALF samples.T cell subsets(CD3^(+),CD69^(+),CD25^(+)and HLA-DR^(+))in BALF samples were analyzed by flow cytometry.Interleukin(IL)-6,IL-10,IL-2,tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ)and transforming growth factor-β(TGF-β)in BALF samples were detected by enzyme linked immunosorbent assay.Results:The detection rate of HPIV-3 genotype was 83.78%(31/37).The whole blood white blood cell count,neutrophil count and lymphocyte count in acute phase were higher than those in recovery phase,but the hemoglobin level and red blood cell count were lower than those in recovery phase(P<0.05).Compared with the convalescent stage,the CD3^(+)T cell count in acute stage BALF samples decreased,but the CD69^(+)T cell count,CD25^(+)T cell count,HLA-DR^(+)T cell count increased,and the ratio of CD4^(+)/CD8^(+)increased(P<0.05).In addition,the levels of IL-6,IL-2,TNF-αand IFN-γin BALF samples in acute stage were higher than those in recovery stage(P<0.05).The levels of CD69^(+),CD4^(+)/CD8^(+),IL-10,IL-2 and IFN-γin the moderate and severe BALF samples at acute stage were higher than those in the mild group,while the level of CD3^(+)was lower than that in the mild group(P<0.05).Compared with the moderate group,the levels of CD69^(+),CD4^(+)/CD8^(+),IL-10,IL-2 and IFN-γwere further increased in the severe group,while the level of CD3^(+)was further decreased in the moderate group(P<0.05).Conclusion:Activated T cells play an important role in the pathogenesis of HIPVs infection,which may be an important immunological and clinical surveillance tool for identifying viral infections in children.