ISG15 and Autoimmunity: Importantly, the IFN-sensitive genes included in autoimmunity signatures of RA,48 systemic lupus erythematosus49 and Sjögren’s syndrome50 (e.g., IRF7, GAS6, IFI35, IFITM2, ISG15, ISG20, ODF3B) were also downregulated (Figure 3I).