Department of Infectious, Respiratory, and Digestive Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan.
World J Gastroenterol. 2012 Dec 21;18(47):6974-80. doi: 10.3748/wjg.v18.i47.6974.
To investigate the utility of immunohistochemical (IHC) staining with an antibody to Mycobacterium tuberculosis (M. tuberculosis) for the diagnosis of intestinal tuberculosis (TB).
We retrospectively identified 10 patients (4 males and 6 females; mean age = 65.1 ± 13.6 years) with intestinal TB. Clinical characteristics, including age, gender, underlying disease, and symptoms were obtained. Chest radiograph and laboratory tests, including sputum Ziehl-Neelsen (ZN) staining, M. tuberculosis culture, and sputum polymerase chain reaction (PCR) for tubercle bacilli DNA, as well as Tuberculin skin test (TST) and QuantiFERON-TB gold test (QFT), were examined. Colonoscopic records recorded on the basis of Sato's classification were also reviewed, in addition to data from intestinal biopsies examined for histopathological findings, including hematoxylin and eosin staining, and ZN staining, as well as M. tuberculosis culture, and PCR for tubercle bacilli DNA. For the present study, archived formalin-fixed paraffin-embedded (FFPE) intestinal tissue samples were immunohistochemically stained using a commercially available species-specific monoclonal antibody to the 38-kDa antigen of the M. tuberculosis complex. These sections were also stained with the pan-macrophage marker CD68 antibody.
From the clinical data, we found that no patients were immunocompromised, and that the main symptoms were diarrhea and weight loss. Three patients displayed active pulmonary TB, six patients (60%) had a positive TST, and 4 patients (40%) had a positive QFT. Colonoscopic findings revealed that all patients had type 1 findings (linear ulcers in a circumferential arrangement or linear ulcers arranged circumferentially with mucosa showing multiple nodules), all of which were located in the right hemicolon and/or terminal ileum. Seven patients (70%) had concomitant healed lesions in the ileocecal area. No acid-fast bacilli were detected with ZN staining of the intestinal tissue samples, and both M. tuberculosis culture and PCR for tubercle bacilli DNA were negative in all samples. The histopathological data revealed that tuberculous granulomas were present in 4 cases (40%). IHC staining in archived FFPE samples with anti-M. tuberculosis monoclonal antibody revealed positive findings in 4 patients (40%); the same patients in which granulomas were detected by hematoxylin and eosin staining. M. tuberculosis antigens were found to be mostly intracellular, granular in pattern, and primarily located in the CD68(+) macrophages of the granulomas.
IHC staining with a monoclonal antibody to M. tuberculosis may be an efficient and simple diagnostic tool in addition to classic examination methods for the diagnosis of intestinal TB.
探讨抗结核分枝杆菌抗体免疫组织化学（IHC）染色在诊断肠结核（TB）中的应用。
我们回顾性分析了 10 例肠结核患者（4 名男性和 6 名女性；平均年龄=65.1±13.6 岁）。获取了患者的临床特征，包括年龄、性别、基础疾病和症状。检查了包括痰 Ziehl-Neelsen（ZN）染色、结核分枝杆菌培养和痰结核分枝杆菌 DNA 聚合酶链反应（PCR）、结核菌素皮肤试验（TST）和 QuantiFERON-TB gold 试验（QFT）在内的胸部 X 线检查和实验室检查。此外，还回顾了基于 Sato 分类的结肠镜记录，并对肠活检的组织病理学检查数据进行了评估，包括苏木精和伊红染色、ZN 染色、结核分枝杆菌培养和结核分枝杆菌 DNA PCR。对于本研究，使用市售的结核分枝杆菌复合物 38kDa 抗原种特异性单克隆抗体对存档的福尔马林固定石蜡包埋（FFPE）肠组织样本进行了免疫组织化学染色，并使用泛巨噬细胞标志物 CD68 抗体对这些切片进行了染色。
从临床数据来看，我们发现没有免疫功能低下的患者，主要症状是腹泻和体重减轻。3 例患者有活动性肺结核，6 例（60%）TST 阳性，4 例（40%）QFT 阳性。结肠镜检查发现所有患者均有 1 型表现（线性溃疡呈环形排列或线性溃疡呈环形排列，伴有黏膜出现多个结节），均位于右半结肠和/或末端回肠。7 例（70%）患者同时伴有回盲部愈合性病变。肠组织样本的 ZN 染色未检测到抗酸杆菌，结核分枝杆菌培养和结核分枝杆菌 DNA PCR 均为阴性。组织病理学数据显示，4 例（40%）存在结核性肉芽肿。用抗结核分枝杆菌单克隆抗体对存档的 FFPE 样本进行免疫组织化学染色显示，4 例（40%）患者阳性；这些患者的肉芽肿也通过苏木精和伊红染色检测到。分枝杆菌抗原主要位于肉芽肿的 CD68（+）巨噬细胞内，呈颗粒状，模式呈颗粒状。
抗结核分枝杆菌单克隆抗体免疫组织化学染色可能是一种有效的、简单的诊断工具，除了经典的检查方法外，还可用于诊断肠结核。
