CXCL8 and myeloid sarcoma: Interestingly, PBMCs isolated from healthy subjects and RR-MS patients were unresponsive to poly(I⋅C) stimulation, both in terms of TNF-α and IL-8 production (Figures 4C,D), indicating that PBMCs from control individuals and RR-MS patients are refractory to TLR3 stimulation, in terms of TNF-α and IL-8 signaling.