In patients with progressive MS, single-cell mass cytometry analysis has shown that highly phagocytic and activated microglia downregulate the expression of homeostatic markers (such as P2Y12 and GPR56) and upregulate the expression of proteins involved in microglial activation and phagocytic activity including CD68, CCR2, CD64, CD32, CD95, and CCL4 [61]. This evidence concerns the gene CCL4 and myeloid sarcoma.