ARG1 and systemic sclerosis: Here we found that “regulation of vasculature development” was a Biological Process super cluster in the GO analysis of DE genes unique to SSc-PF, and PTGS2, ARG1 and EDN1 were related hub proteins under the subcategories “tube development” and “blood circulation.” This is consistent with vascular complications and angiogenesis impairment being trademarks in SSc patients (89), and with structural disintegration of vasculature and loss of endothelial cell numbers observed in late stage of SSc-PF (2).