IFNG and infection: Humans with genetic deficiencies in IFN-γ as well as IL-12, which is produced by the monocyte/macrophage lineage, and/or their receptors are particularly susceptible to uncontrollable infection by MTb and by otherwise non-pathogenic strains of atypical mycobacteria and by Mycobacterium bovis bacillus Calmette-Guerin (BCG) [5], [20], [21], [22], [23].