TNF and myeloid sarcoma: The current paper aimed to evaluate the presence of SGs in OLs as an indicator of injury in situ in MS tissues and use dissociated cultures of human brain-derived OLs to define the mechanisms that regulate the development and persistence of SGs in response to acute stress (sodium arsenite, SA) or chronic metabolic stress (glucose/nutrient deprivation) and inflammatory cytokines (TNFα, IFNγ).