Mustafa Tehmina, Wiker Harald G, Mfinanga Sayoki G M, Mørkve Odd, Sviland Lisbet
Centre for International Health, University of Bergen, Bergen, Norway.
Mod Pathol. 2006 Dec;19(12):1606-14. doi: 10.1038/modpathol.3800697. Epub 2006 Sep 15.
The clinical and histological criteria used to diagnose lymphadenitis caused by Mycobacterium tuberculosis complex organisms have poor specificity. Acid-fast staining and culture has low sensitivity and specificity. We report a novel method for diagnosis of tuberculosis that uses immunohistochemistry to detect the secreted mycobacterial antigen MPT64 on formalin-fixed tissue biopsies. This antigen has not been detected in non-tuberculous mycobacteria. Polymerase chain reaction (PCR) for amplification of IS6110 from DNA obtained from the biopsies was used as a gold standard. Fifty-five cases of granulomatous lymphadenitis with histologically suspected tuberculosis obtained from Norway and Tanzania were evaluated. Four known tuberculosis cases were used as positive controls, and 16 biopsies (12 foreign body granulomas and four other non-granulomatous cases) as negative controls. With immunohistochemistry, 64% (35/55) and with PCR, 60% (33/55) of granulomatous lymphadenitis cases were positive. Using PCR as the gold standard, the classical tuberculosis histology had sensitivity, specificity, positive and negative predictive values of 92, 37, 60, and 81%, respectively, and immunohistochemistry had sensitivity, specificity, positive and negative predictive values of 90, 83, 86, and 88%, respectively. The observed agreement between PCR and immunohistochemistry was 87% (kappa = 0.73). Immunohistochemistry with anti-MPT64 antiserum is a rapid, sensitive, and specific method for establishing an etiological diagnosis of tuberculosis in histologic specimens. Immunohistochemistry has the advantages over PCR of being robust and cheap, and it can easily be used in a routine laboratory.
用于诊断结核分枝杆菌复合群生物体引起的淋巴结炎的临床和组织学标准特异性较差。抗酸染色和培养的敏感性和特异性较低。我们报告了一种诊断结核病的新方法，该方法利用免疫组织化学在福尔马林固定的组织活检标本上检测分泌的分枝杆菌抗原MPT64。在非结核分枝杆菌中未检测到这种抗原。从活检标本中获取的DNA进行IS6110聚合酶链反应（PCR）扩增被用作金标准。对从挪威和坦桑尼亚获得的55例组织学怀疑为结核病的肉芽肿性淋巴结炎病例进行了评估。4例已知结核病病例用作阳性对照，16例活检标本（12例异物肉芽肿和4例其他非肉芽肿病例）用作阴性对照。免疫组织化学检测显示，55例肉芽肿性淋巴结炎病例中有64%（35/55）呈阳性，PCR检测显示60%（33/55）呈阳性。以PCR作为金标准，经典结核病组织学的敏感性、特异性、阳性预测值和阴性预测值分别为92%、37%、60%和81%，免疫组织化学的敏感性、特异性、阳性预测值和阴性预测值分别为90%、83%、86%和88%。PCR与免疫组织化学之间的观察一致性为87%（kappa = 0.73）。用抗MPT64抗血清进行免疫组织化学是一种快速、敏感且特异的方法，可用于在组织学标本中确立结核病的病因诊断。免疫组织化学相对于PCR具有稳健、廉价的优点，并且可以很容易地在常规实验室中使用。
