TLR4 and myeloid sarcoma: Ligation of TLR3 and TLR4, by poly(I:C) and LPS respectively, leads to microglial activation and consequently stimulates secretion of cytokines IL-12, TNFα, IL-6, IL-10 and chemokine CXCL-10 (a chemoattractant for pro-inflammatory T cells), which are strongly associated with MS pathogenesis (Jack et al., 2005).