Abstract：
The diagnosis of extrapulmonary tuberculosis (EPTB) poses a significant challenge, with controversies surrounding the accuracy of IFN-γ release assays (IGRAs). This study aimed to assess the diagnostic accuracy of RD1 immunodominant T-cell antigens, including ESAT-6, CFP-10, PE35, and PPE68 proteins, for immunodiagnosis of EPTB. Twenty-nine patients with EPTB were enrolled, and recombinant PE35, PPE68, ESAT-6, and CFP-10 proteins were evaluated in a 3-day Whole Blood Assay. IFN-γ levels were measured using a Human IFN-γ ELISA kit, and the QuantiFERON-TB Gold Plus (QFT-Plus) test was performed. Predominantly, the patients were of Afghan (62%, n = 18) and Iranian (38%, n = 11) nationalities. Eighteen individuals tested positive for QFT-Plus, accounting for 62% of the cases. The positivity rate for IGRA, using each distinct recombinant protein (ESAT-6, PPE68, PE35, and CFP-10), was 72% (n = 21) for every protein tested. Specifically, among Afghan patients, the positivity rates for QFT-Plus and IGRA using ESAT-6, PPE68, PE35, and CFP-10 were 66.7%, 83.3%, 83.3%, 77.8%, and 88.9%, respectively. In contrast, among Iranian patients, the positivity rates for the same antigens were 54.5%, 54.5%, 54.5%, 63.6%, and 45.5%, respectively. In conclusion, our study highlights the potential of IGRA testing utilizing various proteins as a valuable diagnostic tool for EPTB. Further research is needed to elucidate the underlying factors contributing to these disparities and to optimize diagnostic strategies for EPTB in diverse populations.
摘要：
肺外结核（EPTB）的诊断提出了重大挑战，围绕IFN-γ释放测定(IGRAs)的准确性存在争议。本研究旨在评估RD1免疫显性T细胞抗原的诊断准确性。包括ESAT-6、CFP-10、PE35和PPE68蛋白，用于EPTB的免疫诊断。纳入29例EPTB患者，重组PE35、PPE68、ESAT-6和CFP-10蛋白在3天的全血试验中进行评价。使用人IFN-γELISA试剂盒测量IFN-γ水平，并进行QuantiFERON-TBGoldPlus(QFT-Plus)测试。主要是,病人是阿富汗人(62%，n=18)和伊朗人(38%，n=11)国籍。18个人的QFT-Plus检测呈阳性，占病例的62%。IGRA的阳性率，使用每种不同的重组蛋白（ESAT-6，PPE68，PE35和CFP-10），每个测试的蛋白质为72%(n=21)。具体来说,在阿富汗患者中，使用ESAT-6，PPE68，PE35和CFP-10的QFT-Plus和IGRA阳性率为66.7％，83.3%,83.3%,77.8%,88.9%,分别。相比之下,在伊朗患者中，相同抗原的阳性率为54.5%,54.5%,54.5%,63.6%,和45.5%，分别。总之,我们的研究强调了利用各种蛋白质作为有价值的EPTB诊断工具的IGRA检测的潜力.需要进一步的研究来阐明导致这些差异的潜在因素，并优化不同人群中EPTB的诊断策略。
