Aiming to identify a possible biomarker that distinguishes immune cellular response of active tuberculosis from latent infection. Peripheral blood mononuclear cells (PBMCs) of pulmonary tuberculosis patients (PTB), tuberculin positive household contacts (TST+ HHC), and tuberculin negative non-household contacts (TST− Non HHC) were stimulated with PPD or CFP-10 and the percentage of CD69⁺ cells, proliferating precursor and IFN-γ producing CD4⁺, CD8⁺, CD56⁺CD3⁻ and CD56⁺CD3⁺ cells were compared. IL-2, IL-12p70, IL-15, IL-18 and IL-10 were measured in culture supernatants. PTB and TST+ HHC presented higher percentages of CD69⁺ cells, IFN-γ⁺ and proliferating precursors in all subpopulations studied and higher IL-12p70 levels than TST− Non HHC. The increased percentage of IFN-γ producing CD56⁺CD3⁺ cells in response to CFP-10 in PTB, compared with TST− Non HHC and the ratios between the percentage of CD56⁺CD3⁺ cells/CD56⁺CD3⁻ and CD8⁺ cells producing IFN-γ suggest that these parameters may distinguish active TB from latently infected individuals.