STAT1 and systemic lupus erythematosus: We observed a trend toward increased gene expression in certain subsets for downstream pathway members IKKε (IKBKE), TBK1 (TBK1) and significant increases in the expression of multiple transcription factors as mentioned above, such as IRF1 and STAT3 in myeloid cells and IRF7 and STAT1 in all SLE PBMC subsets, as shown in Figure 5C.