IL6 and autoimmune disease: In support of this dual role, recent work has demonstrated that during cerebrovascular injury, whether induced by stroke, neurodegeneration, TBI, or autoimmune disease, infiltrating monocytes are the primary source of IL-6 and are required for instructing microglia to repair the damaged vasculature and promote recovery.79 Furthermore, Frieler and collaborators reported that depletion of monocytes/macrophages during TBI results in a marked increase in proinflammatory gene expression in the injured brain.80