P2RY12, which is an important sensor of extracellular nucleotides released early after damage, was reduced in activated microglia after LPS injection into the striatum (Haynes et al., 2006) or peritoneal cavity (Hirbec et al., 2018), and in microglia within human MS lesions (Zrzavy et al., 2017). Here, P2RY12 is linked to myeloid sarcoma.