A recent study investigating the different cytokines profiles including IFN-γ, IL-2 and TNF-α in Mtb-specific CD4+ T cells have shown that the proportion of single-positive TNF-α Mtb-specific CD4+ T cells was the strongest predictive measure of discrimination between active disease and latent infection [25]. The gene discussed is IFNG; the disease is disease arising from reactivation of latent virus.