Xu Xiang, Golden Jeffrey A, Dolganov Gregory, Jones Kirk D, Donnelly Samantha, Weaver Timothy, Caughey George H
Department of Medicine University of California at San Francisco, San Francisco, 94143, USA.
J Heart Lung Transplant. 2005 Aug;24(8):1055-66. doi: 10.1016/j.healun.2004.06.016.
Rejection and obliterative bronchiolitis are barriers to sustained graft function in recipients of transplanted lungs. Early detection is hindered by inadequate tests and an incomplete understanding of the molecular events preceding or accompanying graft deterioration.
Hypothesizing that genes involved in immune responses and tissue remodeling produce biomarkers of rejection, we measured the expression of 192 selected genes in 72 sets of biopsy specimens from human lung allografts. Gene transcripts were quantified using a 2-step, multiplex, real-time polymerase chain reaction approach in endobronchial and transbronchial biopsy specimens from transplant recipients without acute infections undergoing routine surveillance bronchoscopy.
Comparisons of histopathology in parallel biopsy specimens identified 6 genes correlating with rejection as manifested by lymphocytic bronchitis, a suspected harbinger of obliterative bronchiolitis. For example, beta2-defensin and collagenase transcripts in inflamed bronchi increased 37-fold and 163-fold, respectively. By contrast, these transcripts did not correlate with acute rejection in transbronchial specimens. Further, no correspondence was noted between histopathologic bronchitis and parenchymal rejection when endobronchial and transbronchial samples were obtained from the same patient.
Our highly sensitive method permits quantitation of many gene transcripts simultaneously in small, bronchoscopically acquired biopsy specimens of allografts. Transcript signatures obtained by this approach suggest that airway and alveolar responses to rejection differ and that endobronchial biopsy specimens assess lymphocytic bronchitis and chronic rejection but are not proxies for transbronchial biopsy specimens. Further, they reveal changes in airway expression of the specific genes involved in host defense and remodeling and suggest that the measurement of transcripts correlating with lymphocytic bronchitis may be diagnostic adjuncts to histopathology.
排斥反应和闭塞性细支气管炎是肺移植受者移植肺持续发挥功能的障碍。检测手段不足以及对移植肺恶化之前或伴随发生的分子事件理解不全面阻碍了早期诊断。
假设参与免疫反应和组织重塑的基因可产生排斥反应的生物标志物，我们检测了取自人肺同种异体移植的72套活检标本中192个选定基因的表达。采用两步法多重实时聚合酶链反应方法对接受常规监测支气管镜检查、无急性感染的移植受者的支气管内和经支气管活检标本中的基因转录本进行定量。
对平行活检标本的组织病理学比较发现，有6个基因与以淋巴细胞性支气管炎为表现的排斥反应相关，淋巴细胞性支气管炎被怀疑是闭塞性细支气管炎的先兆。例如，发炎支气管中的β2 - 防御素和胶原酶转录本分别增加了37倍和163倍。相比之下，这些转录本与经支气管标本中的急性排斥反应无关。此外，当从同一患者获取支气管内和经支气管样本时，组织病理学上的支气管炎与实质排斥反应之间未发现对应关系。
我们的高灵敏度方法能够在通过支气管镜获取的同种异体移植小活检标本中同时对许多基因转录本进行定量。通过这种方法获得的转录本特征表明，气道和肺泡对排斥反应的应答不同，支气管内活检标本可评估淋巴细胞性支气管炎和慢性排斥反应，但不能替代经支气管活检标本。此外，它们揭示了参与宿主防御和重塑的特定基因在气道中的表达变化，并表明与淋巴细胞性支气管炎相关的转录本测量可能是组织病理学的诊断辅助手段。
