1 Leuven Lung Transplant Unit, Katholieke Universiteit Leuven and Universitair Ziekenhuis Gasthuisberg, Leuven, Belgium.
Am J Respir Crit Care Med. 2014 Feb 1;189(3):292-300. doi: 10.1164/rccm.201310-1894OC.
The chronic rejection of lung allografts is attributable to progressive small airway obstruction.
To determine precisely the site and nature of this type of airway obstruction.
Lungs from patients with rejected lung allografts treated by a second transplant (n = 7) were compared with unused donor (control) lungs (n = 7) using multidetector computed tomography (MDCT) to determine the percentage of visible airways obstructed in each airway generation, micro-computed tomography (microCT) to visualize the site of obstruction, and histology to determine the nature of this obstruction.
The number of airways visible with MDCT was not different between rejected and control lungs. However, 10 ± 7% of observed airways greater than 2 mm in diameter, 50 ± 22% of airways between 1 and 2 mm in diameter, and 73 ± 10% of airways less than 1 mm in diameter were obstructed in the rejected lungs. MicroCT confirmed that the mean lumen diameter of obstructed airways was 647 ± 317 μm but showed no difference in either total number and cross-sectional area of the terminal bronchioles or in alveolar dimensions (mean linear intercept) between groups (P > 0.05). In addition, microCT demonstrated that only segments of the airways are obstructed. Histology confirmed a constrictive form of bronchiolitis caused by expansion of microvascular-rich granulation tissue in some locations and collagen-rich scar tissue in others.
Chronic lung allograft rejection is associated with a progressive form of constrictive bronchiolitis that targets conducting airways while sparing larger airways as well as terminal bronchioles and the alveolar surface.
慢性排斥反应导致肺同种异体移植物发生进行性小气道阻塞。
明确这种类型的气道阻塞的确切部位和性质。
采用多排 CT（MDCT）比较了 7 例接受再次移植治疗的排斥肺同种异体移植物患者和 7 例未使用的供体肺（对照）的肺，以确定每个气道分支中可见气道阻塞的百分比；采用微计算机断层扫描（microCT）观察阻塞部位；采用组织学确定这种阻塞的性质。
MDCT 显示可见气道数量在排斥肺和对照肺之间没有差异。然而，在直径大于 2mm 的观察气道中，有 10±7%的气道、在直径为 1-2mm 的气道中，有 50±22%的气道、在直径小于 1mm 的气道中，有 73±10%的气道被阻塞。microCT 证实阻塞气道的平均管腔直径为 647±317μm，但两组间终末细支气管的总数和横截面积以及肺泡尺寸（线性平均截距）均无差异（P>0.05）。此外，microCT 显示只有气道的部分节段被阻塞。组织学证实，在某些部位，富含微血管的肉芽组织扩张，而在其他部位则是富含胶原的瘢痕组织，导致了一种紧缩性细支气管炎。
慢性肺同种异体移植物排斥与进行性紧缩性细支气管炎有关，这种细支气管炎主要靶向传导气道，而较大气道以及终末细支气管和肺泡表面则不受影响。
