USP18 and systemic lupus erythematosus: The IGS transcripts not DE between purified cells were also of interest; IFI27, IFI44L, IFIH1, IFIT3, OASL, RSAD2, SPATS2L, and USP18 were all highly DE when each cell type was compared to controls, but not DE between SLE T cells, B cells or monocytes (Supplementary Data 30 and 31).