A flow cytometric assay measuring Mycobacterium tuberculosis-specific CD4 T-cell responses using co-expression of CD25/CD134 (OX40 assay) was explored as a diagnostic tool for active tuberculosis (TB) in a Thai population with and without HIV infection. Peripheral blood mononuclear cells (PBMC) obtained from 133 participants at TB diagnosis were cryopreserved. Seventy-six participants had a clinical diagnosis of TB which were confirmed by a positive culture. CD4 T-cell responses were measured after stimulation with a pool of overlapping peptides covering RD-1 antigens: CFP-10 + ESAT-6. The performance of the assay was also compared to the Xpert MTB/RIF assay. The overall sensitivity of the OX40 assay was 94.7% (95%CI 87.1-98.5); its specificity was 71.9% (95%CI, 58.5-83). The sensitivity of the OX40 assay among HIV-infected participants was 100% (95%CI, 88.8-100) with a specificity of 92.9% (95%CI, 66.1-99.8). OX40 assay performed particularly well in those with active TB and HIV infection.

中文翻译：

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一种简单的流式细胞术在诊断活动性结核病中的表现

使用 CD25/CD134 共表达（OX40 测定）测量结核分枝杆菌特异性 CD4 T 细胞反应的流式细胞术被探索作为泰国人群中活动性结核病 (TB) 的诊断工具，无论是否感染 HIV。从 133 名结核病诊断参与者获得的外周血单核细胞 (PBMC) 被冷冻保存。76 名参与者的临床诊断为 TB，经阳性培养证实。在用覆盖 RD-1 抗原的重叠肽池刺激后测量 CD4 T 细胞反应：CFP-10 + ESAT-6。还将该测定的性能与 Xpert MTB/RIF 测定进行了比较。OX40 检测的总体灵敏度为 94.7% (95% CI 87.1-98.5)；其特异性为 71.9% (95% CI, 58.5-83)。OX40 检测在 HIV 感染者中的敏感性为 100%（95%CI，88.8-100），特异性为 92.9%（95%CI，66.1-99.8）。OX40 检测在活动性结核病和 HIV 感染者中表现特别好。