CD74 and myeloid sarcoma: Further, in the early disease stages of MS and in a mouse model of demyelination, homeostatic microglial genes such as P2RY12, TMEM119 and CX3CR1 were downregulated in active lesions, whereas genes associated with microglia states SPP1, CD74 and CTSD and the cytokine CCL4 were upregulated [12, 13].