Taheri Mohammad, Bazrafkan Hamid, Habibagahi Mojtaba
Department of Microbiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Immunotherapy laboratory, Department of Immunology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Iran Red Crescent Med J. 2013 Jun;15(6):477-82. doi: 10.5812/ircmj.3635. Epub 2013 Jun 5.
Classical screening methods are incapable to properly detect LTBI (Latent TB Infection) and HCWs (Healthcare Workers) are at the high risk of exposure. Only few reports estimated the prevalence of LTBI among Iranian HCWs and they mostly used the TST (Tuberculin Skin Test), rather than assessing the response against TB-specific antigens.
The current study aimed to determine the frequency of IFN - γ producing blood cells of microbiology and radiology ward technicians by an in-house IFN - γ ELISPOT assay in the University hospitals of Shiraz University of Medical Sciences (SUMS) against recombinant ESAT - 6 and PPD antigens.
89 HCWs from medical laboratory and radiology departments of Shiraz University of Medical Sciences' hospitals, South of Iran, were screened for LTBI. To achieve the goal, an in-house IFN - γ (Interferon - gamma) ELISPOT (Enzyme Linked ImmunoSpot) assay was used to detect the reactivity against ESAT - 6 (Early Secreted Antigen Target protein - 6) and the PPD (Purified Protein Derivate).
Almost 8% of the personnel showed positive TST (over 10 mm) reaction while 29% of them had considerable T - cell reactivity against PPD in ELISPOT assays. However, the ESAT - 6 reactivity was found only in one case of HCWs. No correlation was found between the patterns of the reactions and the age or the duration of the employment or previous vaccination history of the participants. The ELISPOT results were not correlated with the TST results.
Considering the hindrance of TST, the IFN - γ ESAT - 6 ELISPOT assay, even in forms of in-house tests, could replace traditional methods to properly spot the LTBI among the high risk groups from Iran's health system.
传统筛查方法无法准确检测潜伏性结核感染（LTBI），医护人员（HCWs）面临较高的暴露风险。仅有少数报告估计了伊朗医护人员中LTBI的患病率，且大多使用结核菌素皮肤试验（TST），而非评估针对结核特异性抗原的反应。
本研究旨在通过设拉子医科大学（SUMS）大学医院内部的干扰素-γ酶联免疫斑点（IFN-γ ELISPOT）检测法，测定微生物学和放射科病房技术人员中产生干扰素-γ的血细胞针对重组早期分泌抗原靶蛋白6（ESAT-6）和纯化蛋白衍生物（PPD）抗原的频率。
对伊朗南部设拉子医科大学医院医学检验和放射科的89名医护人员进行LTBI筛查。为实现这一目标，采用内部干扰素-γ（IFN-γ）酶联免疫斑点（ELISPOT）检测法检测针对ESAT-6（早期分泌抗原靶蛋白-6）和PPD（纯化蛋白衍生物）的反应性。
近8%的人员TST反应呈阳性（超过10毫米），而在ELISPOT检测中，29%的人员对PPD有显著的T细胞反应性。然而，仅在1名医护人员中发现了对ESAT-6的反应性。未发现反应模式与参与者的年龄、工作年限或既往疫苗接种史之间存在相关性。ELISPOT结果与TST结果不相关。
考虑到TST的局限性，即使是内部检测形式的IFN-γ ESAT-6 ELISPOT检测法，也可替代传统方法，准确筛查伊朗卫生系统高危人群中的LTBI。
