ERN1 and myeloid sarcoma: IRE1 via XBP1s controls eosinophil, DC, and plasma cell development (Reimold et al., 2001; Iwakoshi et al., 2007; Bettigole et al., 2015), which contribute to neuroinflammation in MS and Experimental Autoimmune Encephalomyelitis (EAE), the mouse model of MS (Greter et al., 2005; Wensky et al., 2005; Mundt et al., 2019; Pröbstel et al., 2020).