支气管肺泡灌洗液真菌1，3-β-D葡聚糖对侵袭性肺部真菌感染诊断的临床价值

Diagnostic value of using 1,3-β-D-glucan in BALF to detect an invasive pulmonary fungal infection

目的探讨支气管肺泡灌洗液中真菌1,3-β-D葡聚糖在肺部疾病合并侵袭性真菌感染诊断中的价值。方法收集山东省淄博市解放军第148医院呼吸消化科确诊的慢性阻塞性肺疾病合并侵袭性真菌感染患者、细菌性肺炎患者及健康志愿者的血浆及支气管肺泡灌洗液,用MB-80微生物动态快速检测系统定量检测真菌1,3-β-D葡聚糖浓度。结果健康组血浆1,3-β-D浓度为(12.90±7.55)pg/ml,细菌性肺炎组为(15.7±8.31)pg/ml,与上述两对照组相比,1,3-β-D葡聚糖在慢性阻塞性肺疾病合并侵袭性真菌感染组血浆中的浓度(38.2±30.4pg/ml)明显升高(P<0.05),而健康组与细菌性肺炎组间无统计学差异。健康组支气管肺泡灌洗液1,3-β-D浓度为(14.05±10.46)pg/ml,细菌性肺炎组为(17.65±8.33)pg/ml,与上述两对照组相比,1,3-β-D葡聚糖在慢性阻塞性肺疾病合并侵袭性真菌感染组支气管肺泡灌洗液中的浓度(239.30±228.31pg/ml)明显升高(P<0.05),而健康组与细菌性肺炎组间无统计学差异。与血浆相比,慢性阻塞性肺疾病合并侵袭性真菌感染组肺泡灌洗液中1,3-β-D葡聚糖浓度明显升高。不同真菌感染患者肺泡灌洗液中1,3-β-D葡聚糖浓度差异无统计学意义(P>0.05)。检测肺泡灌洗液和血浆1,3-β-D葡聚糖浓度,以20pg/ml作为诊断阈值时前者的敏感性为95%、特异性为93%、阳性预测值为82%及阴性预测值为90%;后者的敏感性为75%、特异性为90%、PPV为66%及阴性预测值为91%。结论与对照组相比,慢性阻塞性肺疾病合并侵袭性真菌感染组支气管肺泡灌洗液与血浆中1,3-β-D葡聚糖浓度都明显升高;支气管肺泡灌洗液1,3-β-D葡聚糖对肺部真菌感染(除外新生儿隐球菌感染)的诊断较血浆更灵敏、特异,但无法鉴别感染真菌的种类。

Objectives One aim of this study was to detect levels of 1,3-β-D-glucan （BDG） in blood and BALF from patients with chronic obstructive pulmonary disease （COPD） and invasive FungaL infections （IFI） （COPD＆IFI） and another aim was to determine the possible value of using a fungal BDG test （G test） to diagnose lung disease and an IFI. Methods Samples were collected from 56 patients with COPD＆IFI, 4,2 patients with bacterial pneumonia, and 10 healthy controls from January 2012 to December 2014 in Hospital No. 148 of the PLA. With written informed consent, BALF and blood samples were collected from all subjects before treatment with antifungal agents. Levels of BDG in BALF and plas- ma were measured using an MB-80 microbial rapid dynamic testing system from Beijing Jinshanchuan Company. Results Levels of BDG in plasma were （12.90±7.55）pg/ml in the healthy group, （15.7＋8.31）pg/ml in the bacterial pneumo- nia group, and （38.2±30.4）pg/ml in the COPD＆IFI group. Levels of BDG in plasma were significantly higher in the COPD＆IFI group than those in the other two control groups （P〈0.05）, but there was no difference in those levels in the bacterial pneumonia group and the healthy control group （P〉0.05）. Levels of BDG in BALF were （14.05±10.46） pg/ml in the healthy group, 17.65±8.33 pg/mL in the bacterial pneumonia group, and （239.30±228.31）pg/ml in the COPD＆IFI group. Levels of BDG in BALF were markedly higher in the COPD＆IFI group than those in the other two control groups （P〈0.05）, but there was no difference in those levels in the bacterial pneumonia group and the healthy control group （P〉0.05）. For the COPD＆IFI group, the level of BDG in BLAF was significantly higher than that in plasma （P〉0.05）. There were no differences in the levels of BDG in different groups with a fungal infection. When 20 pg/ml was used as the cut-off value, BDG in BALF had a sensitivity of 95%, a specificity of 93%, a positive predictive value （PPV） of 88 %, and a negative predictive value of 86 %, while BDG in plasma had a sensitivity of 75 %, a specificity of 93%, a PPV of 66%, and a negative predictive value of 91%. Conclusion Levels of BDG in BALF and plasma from patients with COPD＆IFI were higher than those in BALF and plasma from patients with bacterial pneumonia as well as healthy controls （P〈0.05）. The concordance between the results of BDG detection in BALF and diagnosis of a deep fungal infection is very useful. Compared to BDG in plasma, BDG in BALF is more specific and has a higher PPV. This has certain clinical value for early diagnosis of deep fungal infections except those due to Cryptococcus neoformans. Levels of BDG in BALF did not statistically differ between different lung fungal infections except for those due to C. neoformans.