Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Inje University Sanggye Paik Hospital, Seoul, Korea.
Division of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, IL, USA.
Yale J Biol Med. 2021 Dec 29;94(4):527-535. eCollection 2021 Dec.
Non-tuberculous mycobacterial lung disease (NTM-LD) is most commonly due to species within the complex (MAC) and complex (MAbC). Surgical lung resection, typically a lobectomy or segmentectomy, is occasionally undertaken for individuals with recalcitrant but localized NTM-LD. Since the growth characteristics of MAC (slow growers) and MAbC (rapid growers) as well as their drug susceptibility patterns are significantly different, the objective of this study is to characterize and compare the histopathologic features of the resected lungs due to these two major NTM groups. From 1996 to 2017, 356 patients with NTM-LD due to MAC (n=270), MAbC (n=54), or both (n=32) underwent a total of 404 lobar resections (with the lingula counted as a separate lobe) at the University of Colorado Hospital. We analyzed by microscopy the existing surgical lung tissue sections for bronchiolitis, bronchiolectasis, bronchiectasis, non-necrotizing granuloma (airway, parenchymal, and total), necrotizing granuloma (airway, parenchymal, and total), peri-airway fibrosis, fibrous pleuritis, and lymphoid follicles. There were no significant differences in the presence or absence of most of the histopathologic features of surgically removed lungs due to MAC, MAbC, or both MAC + MAbC. However, there were significantly more necrotizing granulomas (airway, parenchymal, and total) and fibrous pleuritis in MAC compared to MAbC lung diseases. Since necrotizing granulomas may be a sign of inadequate control of the infection, we posit that their presence may be an indication of increased chronicity, increased virulence of MAC compared to MAbC, and/or impaired host immunity against the NTM. Futures studies to determine the root cause of such differences in histopathologic findings in MAC versus MAbC lung disease may spawn new leads on differential pathogenic mechanisms with different NTM, with the goal of aiming for more targeted therapy against both the NTM and the lung damage induced by them.
非结核分枝杆菌肺病（NTM-LD）最常见的原因是复合群（MAC）和复合群（MAbC）中的物种。对于顽固但局限于 NTM-LD 的个体，偶尔会进行外科肺切除术，通常是肺叶切除术或肺段切除术。由于 MAC（生长缓慢）和 MAbC（生长迅速）的生长特征以及药敏模式有很大的不同，本研究的目的是描述和比较这两种主要 NTM 组引起的切除肺的组织病理学特征。1996 年至 2017 年，在科罗拉多大学医院，由于 MAC（n=270）、MAbC（n=54）或两者（n=32）引起的 NTM-LD 患者共 356 例接受了总共 404 例肺叶切除术（将舌段算作单独的肺叶）。我们通过显微镜分析现有的外科肺组织切片，以评估细支气管炎、细支气管扩张、支气管扩张、非坏死性肉芽肿（气道、实质和总）、坏死性肉芽肿（气道、实质和总）、气道周围纤维化、纤维性胸膜炎和淋巴滤泡。由于 MAC、MAbC 或两者 MAC+MAbC 引起的手术切除肺的大多数组织病理学特征的存在或不存在没有显著差异。然而，MAC 比 MAbC 肺病中坏死性肉芽肿（气道、实质和总）和纤维性胸膜炎的数量显著更多。由于坏死性肉芽肿可能是感染控制不足的标志，我们假设其存在可能表明 MAC 比 MAbC 慢性程度更高、毒力更强，以及/或宿主对 NTM 的免疫受损。未来的研究可能会确定 MAC 与 MAbC 肺病之间组织病理学差异的根本原因，从而为不同 NTM 的不同致病机制提供新的线索，目标是针对 NTM 和它们引起的肺损伤进行更有针对性的治疗。
