USP18 and systemic lupus erythematosus: This revealed that three prioritised lupus genes (USP18, STAT1, IFNA1-17) were shared with the 13 category I genes (IFNAR1/2 signal transduction proteins, Fig. 3A) and four prioritised genes (IRF1/5/8 and OAS1) were shared with the 38 category II genes (transcriptional targets of interferon response, Fig. 3B).