TNF and myeloid sarcoma: In the CNS, Th1 cells secrete high volumes of TNF-α and IFN-γ, attracting naïve monocytes and macrophages towards the breach sites, while Th17 cells co-expressing RORγt and T-bet can convert to Th1-like cells (Th17.1) in response to the high levels of IL-12 and IL-27 that characterize MS [94].