To further explore this hypothesis, we evaluated cytokines and inflammatory mediators associated with tuberculosis immunopathology in humans and cattle, such as gamma interferon (IFN-γ), an inducible form of nitric oxide synthase (iNOS), transforming growth factor-beta (TGF-β) and tumor necrosis factor α (TNF-α) (4, 15, 16). Here, NOS2 is linked to tuberculosis.