The binding of CD200 and CD47 to their respective microglial receptors has immunosuppressive effects, maintaining microglia in a ramified, antiphagocytic state.19,26 Here, we investigate the RNA and protein expression of the immune-inhibitory ligands C200 and CD47 and of their respective receptors, CD200R and SIRPα, in NAGM, GM lesions and perilesional GM, and relate these to pathological features of the donors, with the aim of unveiling mechanisms involved in microglia activation and MS-related pathology. The gene discussed is SIRPA; the disease is myeloid sarcoma.