However, clustering changes in gene expression comparing tofacitinib with baseline gene expression showed coregulation of STAT3 with PSMB5 (28), ARID5A (29), and CD274 (programmed cell death ligand 1, PD-L1) (30, 31), which are known downstream targets of STAT3 (Supplemental Figure 9B), suggesting that tofacitinib regulates the macrophage phenotype in skin through STAT3, but not by affecting genes dysregulated in SSc macrophages. This evidence concerns the gene STAT3 and systemic sclerosis.