We also revealed the expression levels of four hub genes in SSc and SSc-PAH PBMCs samples of GSE19617, which indicated the expression level of IFIT2, IFIT3, RSAD2, and PARP14 was significantly higher in PBMCs from SSc-PAH patients than that from SSc patients (Figure 7A). This evidence concerns the gene IFIT2 and systemic sclerosis.