ISG15 and systemic lupus erythematosus: We found 24 ISGs (RSAD2, IFIT3, APOBEC3A, IFIT2, PARP9, DTX3L, PLSCR1, IFI35, ISG15, CMPK2, HERC5, GBP1, IFI27, STAT1, MX1, IRF7, OAS1, OAS2, OAS3, OASL, IFIH1, SIGLEC1, LGALS9 and BST2) which were significantly associated with SLE disease activity (Figures 6A,B, Supplementary Figure S3).