Both the mRNA and protein levels of IFN-γ were significantly higher in SLE patients than in healthy donors (9, 24), and the mRNA levels of type II IFN-inducible genes (IRF1, GBP1, CXCL9, CXCL10, and SERPING1) were elevated in SLE patients. Here, IRF1 is linked to systemic lupus erythematosus.