CX3CL1 and myeloid sarcoma: It has a key role in neuron–microglia cross-talk in physiology and aging, but the exact role of this chemokine in MS pathology still remains unclear, because CX3CL1 appeared to interfere with proinflammatory microglia activity, therefore with neuroprotective effect (Ransohoff and El Khoury, 2015).