CD38 and pulmonary tuberculosis: The TAM-TB assay has been shown to accurately differentiate between active pulmonary TB (aTB) and latent TB infection (LTBI) in different age groups by determination of the phenotypic and functional characteristics of MTB-specific CD4 T cells via flow cytometry (10–12); detection of high frequencies of activated (CD38+, HLA-DR+, and Ki67+), CD27low effector memory MTB-specific CD4 T cells is indicative of active TB.