P2RY12 and myeloid sarcoma: In this study, to distinguish microglia from infiltrating macrophages in active MS lesions, we used either microglia signature markers P2Y12, TMEM119 and GRP56, together with Clec12A, a marker for hematogenic macrophage (Exp-I) or CD14 and CCR2 for monocytes and/or monocyte-derived macrophages (Exp-II and -III) [58].