NOS2 and immune system disorder: Other components that lead to this immune disorder include tumor necrosis factor-α (TNF-α) and -β (TNF-β), prostaglandin E-2 (PGE-2), inducible nitric oxide synthase (iNOS), metalloproteinases, including collagenases (MMP-1, 8, 13), aggrecanases (ADAM-TS4), stromelysin-1 (MMP-3), and gelatinases (MMP-2) [68,80].