IFNG and polyostotic fibrous dysplasia: In the lung, PFD also decreased inflammatory edema, and reduced levels of hydroxyproline, interleukin (IL)-1β, IL-6, IL-12, p40, monocyte chemoattractant protein and interferon (IFN)-γ [36] It also reduced the elevation of lung basic fibroblast growth factor, lung stroma cell derived factor-1α, and IL-18 [36,32] By a different mechanism, induction of arginase, a vital enzyme for collagen synthesis that metabolizes L-arginine to urea and L-ornithine, is altered by PFD treatment, and consequently, levels of collagen contents were reduced in rat lung orthotopic transplants [37].