IRF1 and dermatomyositis: Interestingly, the expression of the downstream effectors of inflammatory cytokines like TGF-β or TNF-α and interferon-γ gradually declined with increasing distance from the granuloma; the expression of Collagen 1A1 (COL1A1), Endoglin (ENG) and Disabled homolog 2 (DAB2), Interferon induced transmembrane protein 3 (IFITM3), CC chemokine ligand 19 (CCL19), Interferon regulatory factor 1 (IRF1), SAA1, and SAA2 were all upregulated in the PM-cluster and progressively decreased through the IM and DM-clusters in both patients (Figure 7B,C).