TLR4 and myeloid sarcoma: TLR4 expression is upregulated in CNS lesions in mice following EAE and in PBMCs from RR-MS and secondary progressive (SP) MS patients (Andersson et al., 2008), which in support of our study, indicates that TLR4 signaling participates in an innate immune response that may shape the inflammatory response in both forms of MS.