IFNG and tuberculosis: Limitations in our understanding of the natural history of Mtb infection have led to the presumption that all otherwise healthy Mtb-exposed individuals with evidence for Mtb-sensitization [demonstrated by a positive Tuberculin skin test (TST) or Mtb-specific interferon-gamma release assay (IGRA)] harbor a latent form of Mtb and thus remain at life-long risk for Tuberculosis disease (TB) [2].