IRF1 and rheumatoid arthritis: Interestingly, the TF motif for interferon regulatory factor 1 (IRF1), which was enriched in the whole Rh.Arth.-like specific enhancer cluster, is also significantly enriched in the shown differentially active enhancer region (empirical p value, 3.293121e−6; fold enrichment: 18.77985) and was previously connected to rheumatoid arthritis [48].