USP18 (Ubiquitin-specific peptidase 18) was a deubiquitinating enzyme, and as a negative regulator of type I IFN (IFN-α and IFN-β) signaling pathway, where IFN-β was effective for treating MS (Sarasin-Filipowicz et al., 2009; Malhotra et al., 2013; Charbit et al., 2015). Here, USP18 is linked to myeloid sarcoma.