Popper H H, Winter E, Höfler G
Institute of Pathology, University of Graz, Medical School, Austria.
Am J Clin Pathol. 1994 Jun;101(6):738-41. doi: 10.1093/ajcp/101.6.738.
Infection with Mycobacterium tuberculosis is a major cause of death worldwide. Identification of mycobacteria in tissue sections is usually easily achieved by acid-fast stains, but this method sometimes gives unsatisfactory results. The authors therefore compared conventional staining techniques and polymerase chain reaction (PCR) for mycobacterial DNA sequences in 24 selected tissue samples from patients with tuberculosis. In all samples, either positive or negative with acid-fast stain, mycobacterial DNA fragments were detected. In addition, tissue samples from patients with clinically proven sarcoidosis were included as controls. Surprisingly, strong signals for mycobacterial DNA were found in 2 of 15 cases. Polymerase chain reaction is a useful technique in the demonstration of mycobacterial DNA fragments in patients with clinically suspected tuberculosis who have acid fast stain-negative histology. An epithelioid granulomatous reaction in the lung, negative by acid-fast stain and positive for mycobacterial DNA by PCR, however, does not permit a diagnosis of tuberculosis, because a positive result can also be obtained in cases of sarcoidosis. In some cases of sarcoidosis, the causal agent might be either cell wall defective mycobacteria or persistent intracellular DNA from mycobacteria.
结核分枝杆菌感染是全球主要的死亡原因之一。在组织切片中鉴定分枝杆菌通常通过抗酸染色很容易实现，但这种方法有时会给出不令人满意的结果。因此，作者比较了传统染色技术和聚合酶链反应（PCR）在24例肺结核患者选定组织样本中检测分枝杆菌DNA序列的情况。在所有样本中，无论抗酸染色阳性还是阴性，均检测到分枝杆菌DNA片段。此外，将临床确诊的结节病患者的组织样本作为对照。令人惊讶的是，在15例中的2例中发现了分枝杆菌DNA的强信号。聚合酶链反应是一种有用的技术，可用于在临床怀疑患有结核病且抗酸染色组织学阴性的患者中检测分枝杆菌DNA片段。然而，肺部出现抗酸染色阴性且PCR检测分枝杆菌DNA阳性的上皮样肉芽肿反应，并不足以诊断为结核病，因为在结节病病例中也可能得到阳性结果。在某些结节病病例中，病原体可能是细胞壁缺陷型分枝杆菌或分枝杆菌的持续性细胞内DNA。
