Since we previously reported a Nurr1 gene expression down-regulation in PBMCs and in particular in CD4+ T cells and monocytes obtained from MS patients compared to healthy controls (HC) [16]–[18], we decided to activate the Nurr1 signaling pathway in a murine model of MS to better characterize the role of this transcription factor on the EAE pathogenesis. The gene discussed is NR4A2; the disease is myeloid sarcoma.