By considering our results in the context of previous knowledge, we can therefore formulate the following hypothesis: extracellular ATP is increased in CNS tissue as an alarm signal due to progressive homeostasis loss during MS; astrocytes up-regulate P2X7R and MCP-1; this last functions as attractant for peripheral monocytes which in turn down-regulate P2X7R to guarantee their survival and invasion into the CNS tissue, thus contributing to the detrimental effects of neuroinflammation (Figure 9). This evidence concerns the gene CCL2 and myeloid sarcoma.