Highest diagnostic accuracies for active TB (AUC ≥ 0.91) were achieved for: (i) CD27 within IFN-γ<sup>+</sup>TNF-α<sup>+</sup>CD4<sup>+</sup> T-cells in response to ESAT-6/CFP-10, (ii) CD27 and CCR4 markers together within IFN-γ<sup>+</sup>CD4<sup>+</sup> T-cells in response to PPD, and (iii) CD27 MFI ratio performed on IFN-γ<sup>+</sup>TNF-α<sup>+</sup>CD4<sup>+</sup> T-cells after ESAT-6/CFP-10 stimulation.
In contrast, the frequencies of maturation marker CD27 positive MTB-specific CD4 T cells remained largely unchanged until week 26 and significantly differed between subjects with treated TB disease and latent MTB infection (<i>p</i> = 0.0003).
In a study of 81 individuals, divided into four groups based on their HIV-1 status and TB disease activity, we compared the differentiation (CD27 and KLRG1), activation (HLA-DR), homing potential (CCR4, CCR6, CXCR3, and CD161) and functional profiles (IFNγ, IL-2, and TNFα) of <i>Mycobacterium tuberculosis</i> (Mtb)-specific CD4+ T cells using flow cytometry.
the study of CD27 expression using different approaches, whether it involves evaluation of CD45RA expression or not, is a robust biomarker for discriminating TB stages.
These data indicate that down-regulation of CD27 on MTB-specific CD4 T cell could be used as a biomarker of active TB, potentially preceding clinical TB disease.
Altered expression of the genes for TNF-alpha, cathepsin W and TNFRSF7 may be risk factors for the extrapulmonary dissemination of tuberculosis in humans.