Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang road 1095, Wuhan 430030, China.
Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, China.
J Infect. 2020 Jul;81(1):81-89. doi: 10.1016/j.jinf.2020.04.038. Epub 2020 Apr 30.
Distinguishing between active tuberculosis (ATB) and latent tuberculosis infection (LTBI) remains challenging.
The modified T-SPOT.TB assay was performed in 499 participants (243 ATB and 256 LTBI) and another 322 participants (162 ATB and 160 LTBI) who were diagnosed in Qiaokou (training) and Caidian (validation) cohort respectively.
The mean spot sizes (MSS) of early secreted antigenic target 6 (ESAT-6) spot-forming cells (SFC) of T-SPOT.TB assay in ATB patients was significantly higher than that in LTBI individuals. 1.0 × 10 was the optimal number of cells added to phytohaemagglutinin (PHA) well for obtaining more accurate TB-specific antigen to phytohaemagglutinin (TBAg/PHA) ratio. The area under the curve of the diagnostic model by combination of ESAT-6 SFC MSS and modified TBAg/PHA ratio in distinguishing ATB from LTBI was 0.959 in training cohort, with a sensitivity of 90.12% and a specificity of 91.02% when a cutoff value of 0.46 was used. This diagnostic model showed similar performance in the validation cohort. The area under the curve, sensitivity, and specificity were 0.962, 93.21%, and 90.00%, respectively. Further flow cytometry analysis showed that ESAT-6 stimulation induced a significantly higher mean fluorescence intensity of IFN-γ cells in lymphocytes compared with culture filtrate protein 10 (CFP-10) stimulation. In contrast, CFP-10 stimulation induced a significantly higher percentage of IFN-γ cells in lymphocytes compared with ESAT-6 stimulation.
The combination of the MSS of ESAT-6 SFC and the modified TBAg/PHA ratio of T-SPOT.TB assay showed great value in discriminating ATB from LTBI.
区分活动性结核病（ATB）和潜伏性结核感染（LTBI）仍然具有挑战性。
对 499 名参与者（243 名 ATB 和 256 名 LTBI）和另外 322 名参与者（162 名 ATB 和 160 名 LTBI）进行了改良 T-SPOT.TB 检测，这些参与者分别来自硚口（训练）和蔡甸（验证）队列。
ATB 患者 T-SPOT.TB 试验中早期分泌抗原靶 6（ESAT-6）斑点形成细胞（SFC）的平均斑点大小（MSS）明显高于 LTBI 个体。添加到植物血凝素（PHA）孔中的细胞数为 1.0×10时，可获得更准确的结核特异性抗原与植物血凝素（TBAg/PHA）比值。在训练队列中，通过 ESAT-6 SFC MSS 和改良的 TBAg/PHA 比值组合区分 ATB 和 LTBI 的诊断模型的曲线下面积为 0.959，当使用 0.46 作为截断值时，其灵敏度为 90.12%，特异性为 91.02%。该诊断模型在验证队列中表现出相似的性能。曲线下面积、灵敏度和特异性分别为 0.962、93.21%和 90.00%。进一步的流式细胞术分析表明，与培养滤液蛋白 10（CFP-10）刺激相比，ESAT-6 刺激诱导淋巴细胞中 IFN-γ 细胞的平均荧光强度显著升高。相比之下，与 ESAT-6 刺激相比，CFP-10 刺激诱导淋巴细胞中 IFN-γ 细胞的百分比显著升高。
T-SPOT.TB 检测中 ESAT-6 SFC 的 MSS 和改良的 TBAg/PHA 比值的组合在区分 ATB 和 LTBI 方面具有很大的价值。
