Department of Microbiology, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jolly Grant, Dehradun 248140, Uttarakhand, India.
Tuberculosis (Edinb). 2013 Nov;93(6):618-24. doi: 10.1016/j.tube.2013.08.001. Epub 2013 Aug 13.
Differentiation between active and latent TB is a diagnostic challenge in TB-endemic regions. The commercially available IFN-γ-release assays are unsuitable for achieving this discrimination. We, therefore, screened ESAT-6 and CFP-10 proteins through population coverage analysis to identify minimal sets of peptides that can discriminate between these two forms of TB in a North Indian population. Comparing the diagnostic performance of a set of 2 ESAT-6 peptides (positions: 16-36; 59-79) to that of the QuantiFERON(®)-TB Gold IT (QFTGIT) assay, we observed significant difference in IFN-γ and TNF-α levels between patients (n = 15) and their age- and sex-matched healthy household contacts (n = 15). While the mean (±SD) IFNγ titer was 241.8 (±219.24) IU/ml for patients, the same in controls was 564.2 (±334.82) IU/ml (p = 0.039). Similarly the TNFα response was significantly higher in patients, compared to controls (796.47 ± 175.21 IU/ml vs. 481.81 ± 378.72 IU/ml; p = 0.047). IL-4 response to these peptides was non- discriminatory between the two groups. The QFTGIT Assay, however, elicited no significant difference in IFN-γ, TNF-α or IL-4 levels. Hence we conclude that IFN-γ or TNF-α response to these ESAT-6 peptides has the potential to differentiate between active and latent TB in our population.
在结核病流行地区,区分活动性和潜伏性结核病是一个诊断挑战。市售的 IFN-γ 释放检测不适合用于实现这种区分。因此,我们通过人群覆盖分析筛选了 ESAT-6 和 CFP-10 蛋白,以确定可以在印度北部人群中区分这两种形式结核病的最小肽集。比较了一组 2 个 ESAT-6 肽(位置:16-36;59-79)和 QuantiFERON(®)-TB Gold IT(QFTGIT)检测的诊断性能,我们观察到患者(n=15)和年龄、性别匹配的健康家庭接触者(n=15)之间 IFN-γ 和 TNF-α 水平存在显著差异。虽然患者的平均(±SD)IFNγ 滴度为 241.8(±219.24)IU/ml,但对照组的相同值为 564.2(±334.82)IU/ml(p=0.039)。同样,与对照组相比,患者的 TNFα 反应明显更高(796.47±175.21 IU/ml 与 481.81±378.72 IU/ml;p=0.047)。这两组之间对这些肽的 IL-4 反应没有差异。然而,QFTGIT 检测在 IFN-γ、TNF-α或 IL-4 水平上没有引起显著差异。因此,我们得出结论,这些 ESAT-6 肽的 IFN-γ 或 TNF-α 反应有可能在我们的人群中区分活动性和潜伏性结核病。