Scollard D M, Gillis T P, Williams D L
Department of Pathology and Molecular Biology, GWL Hansen's Disease Center at Louisiana State University, Baton Rouge 70894, USA.
Am J Clin Pathol. 1998 May;109(5):642-6. doi: 10.1093/ajcp/109.5.642.
The differentiation of leprosy from other cutaneous granulomatous diseases is routinely based on characteristic histopathologic features and the demonstration of Mycobacterium leprae by acid-fast staining. Increased ascertainment of other mycobacterial infections in the skin has made this task more difficult, but the distinction remains fundamental for the selection of appropriate treatment. Experience with formalin-fixed, paraffin-embedded tissues, frozen tissues, and tissue lysates referred for detection of M. leprae DNA by a polymerase chain reaction (PCR) assay during the past 4 years was reviewed. This assay was done by using primers and probes previously developed in our laboratory to amplify a 360-base-pair fragment of the gene for an 18-kD protein of M. leprae. Among biopsy samples obtained from 37 patients, PCR results were positive for 10 of 20 samples diagnosed as leprosy by histopathologic criteria and in 0 of 17 not diagnosed as leprosy. The specificity of the assay was 100% in this clinical referral material; sensitivity ranged from 50% to 83%. The PCR assay also identified M. leprae in one third of samples in which acid-fast organisms were seen and the histopathologic features were consistent with but not definitive of leprosy. In a nonendemic population, the sensitivity and specificity of PCR assay recommend its use primarily to identify M. leprae when acid-fast organisms are discernible but atypical clinical or histopathologic features obscure the diagnosis. The assay is not highly informative when acid-fast bacilli are not detectable by light microscopy.
麻风病与其他皮肤肉芽肿性疾病的鉴别通常基于特征性的组织病理学特征以及通过抗酸染色显示麻风分枝杆菌。皮肤中其他分枝杆菌感染确诊率的增加使得这项任务更加困难，但这种区分对于选择合适的治疗方法仍然至关重要。回顾了过去4年中通过聚合酶链反应（PCR）检测法检测麻风分枝杆菌DNA的福尔马林固定、石蜡包埋组织、冷冻组织和组织裂解物的经验。该检测使用我们实验室先前开发的引物和探针来扩增麻风分枝杆菌18-kD蛋白基因的一个360碱基对片段。在从37例患者获得的活检样本中，根据组织病理学标准诊断为麻风病的20个样本中有10个PCR结果呈阳性，而17个未诊断为麻风病的样本中PCR结果均为阴性。在这种临床送检材料中，该检测方法的特异性为100%；敏感性范围为50%至83%。PCR检测还在三分之一的样本中鉴定出麻风分枝杆菌，这些样本中可见抗酸菌，且组织病理学特征与麻风病相符但不具有确诊性。在非流行人群中，PCR检测的敏感性和特异性表明，当可识别抗酸菌但非典型的临床或组织病理学特征使诊断模糊时，主要使用该检测来鉴定麻风分枝杆菌。当光学显微镜无法检测到抗酸杆菌时，该检测的信息量不大。
