Several experimental approaches using the EAE model of MS have shown that reducing the CD200-CD200R1 interaction can aggravate the pathology (Hoek et al., 2000; Meuth et al., 2008), while facilitating CD200R1 activation can improve outcomes (Chitnis et al., 2007; Liu et al., 2010). This evidence concerns the gene CD200R1 and myeloid sarcoma.