NOS2 and myeloid sarcoma: A considerable infiltration by macrophages, monocytes, and lymphocytes into central nervous system during MS induces secretion of many activated microglia and astrocytes pro-inflammatory cytokines, including interleukin (IL)-1β, tumor necrosis factor (TNF)-α and IL-6 (Aguzzi et al. 2013; Hartung et al. 1995), which are involved in the production of oxidative radicals (Merrill and Benveniste 1996) and expression of the inducible nitric oxide synthase (iNOS) (Willenborg et al. 1999).