The incidence of infectious disease caused by nontuberculous mycobacteria is increasing worldwide. Pulmonary Mycobacterium avium complex (MAC) disease is difficult to treat with chemotherapy, and its mechanism of infection, infection route, disease onset, and severity remain unknown. Ficolins are oligomeric defense lectins. L-ficolin plays an important role in innate immunity. This study’s aim was to identify L-ficolin’s role in patients with pulmonary MAC disease. Between April 2011 and September 2017, 61 Japanese patients with pulmonary MAC disease were seen at our hospital. A control group, comprising 30 healthy individuals, without respiratory disease were enrolled in our study. The relationship between serum L-ficolin levels and disease severity was assessed, and L-ficolin’s antibacterial role was examined. Serum L-ficolin levels were significantly lower in patients with pulmonary MAC disease than in healthy subjects (1.69 ± 1.27 μg/ml vs. 3.96 ± 1.42 μg/ml; p < 0.001). The cut-off value, based on receiver operating characteristic (ROC) analysis results, was 2.48 μg/ml (area under the curve (AUC) 0.90, sensitivity and specificity 83.6 and 86.7%, respectively). Serum L-ficolin levels were significantly lower in the patients with nodular bronchiectatic type disease compared with the patients with fibrocavitary type disease and were lower in the high-resolution computed tomography high-scoring group compared with low-scoring group. An in vitro analysis showed that purified recombinant L-ficolin bound to M. avium and its major cell wall component, lipoarabinomannan, in a concentration-dependent manner. In addition, recombinant L-ficolin suppressed M. avium growth in a concentration-dependent manner. Insufficient serum L-ficolin is associated with disease progression in pulmonary MAC disease, and the level of serum L-ficolin is a possible biomarker. This study is registered with UMIN ( UMIN000022392 ).

中文翻译：

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血清L-纤维胶蛋白不足与疾病的存在和肺鸟分枝杆菌复杂疾病的程度有关

由非结核分枝杆菌引起的传染病的发病率在世界范围内正在增加。禽鸟分枝杆菌复合物（MAC）疾病很难通过化学疗法治疗，其感染机理，感染途径，疾病发作和严重程度仍然未知。Ficolins是低聚防御凝集素。L-纤维胶蛋白在先天免疫中起重要作用。这项研究的目的是确定L-纤维胶凝蛋白在患有肺MAC疾病的患者中的作用。在2011年4月至2017年9月之间，我院共诊治了61例日本肺部MAC疾病患者。我们的研究纳入了一个由30名健康人组成的对照组，他们没有呼吸道疾病。评估了血清L-纤维胶蛋白水平与疾病严重程度之间的关系，并检查了L-纤维胶蛋白的抗菌作用。患有肺MAC的患者的血清L-纤维胶蛋白水平显着低于健康受试者（1.69±1.27μg/ ml与3.96±1.42μg/ ml； p <0.001）。根据受体工作特征（ROC）分析结果得出的临界值为2.48μg/ ml（曲线下面积（AUC）为0.90，灵敏度和特异性分别为83.6和86.7％）。结节性支气管扩张型疾病患者的血清L-纤维胶蛋白水平显着低于纤维腔积型疾病的患者，而高分辨率计算机断层扫描高得分组的血清L-纤维胶蛋白水平低于低得分组。体外分析表明，纯化的重组L-纤维胶凝蛋白以浓度依赖的方式与鸟分枝杆菌及其主要细胞壁成分lipoarabinomannan结合。另外，重组L-纤维胶蛋白抑制M。鸟生长以浓度依赖性方式。血清L-纤维胶蛋白水平不足与肺MAC疾病的疾病进展有关，并且血清L-纤维胶蛋白水平可能是生物标志物。该研究已在UMIN（UMIN000022392）中注册。