P2RY12 and myeloid sarcoma: In order to investigate P2Y12R and P2X7R as targets for imaging microglia phenotype in MS, we analyzed their expression in white matter samples from three non-neurological controls, three active, two chronic active, and three chronic inactive MS lesions (control, Fig. 2a–d; active, Fig. 2e–l; chronic active, Fig. 2m–p, chronic inactive, Fig. 2q–t; Additional file 1: Figure S2-5).