CD27 and tuberculosis: tuberculosis–specific cellular immune signatures, which have previously been shown to differ between tuberculosis and LTBI: the TNF-α–only TEFF signature [8], the ratio of the median fluorescence intensity of CD27 expression on CD4+ T cells to that of CD27 expression on IFN-γ+ CD4+ T cells (determined by the TAM-TB assay [10]), and the proportion of IFN-γ+ CD4+ T cells with a CD45RA−CD27− or CD45RA−CD27+ phenotype [9].