TLR4 and myeloid sarcoma: In terms of human studies, the expression profile of TLR3 and TLR4 is elevated in active MS brain lesions [15], and TLR4 is upregulated in CSF mononuclear cells from people with MS (pwMS) [16], with data from our laboratory demonstrating that immune cells from pwMS are hypersensitive to LPS in terms of pro-inflammatory cytokine expression [17].