PARP4 and pulmonary arterial hypertension: Scleroderma patients with or without PAH demonstrated a pattern of 30 distinct immune response genes (DAVID [NIH Database for Annotation, Visualization, and Integrated Discovery]: defense response; p<7×10−4) up-regulated in common including CXCL10, FCGR1A, HCK, MX2, NCF1C, PARP4, and TLR4 (see Table S1 for all cited genes, enrichment results, and complete group comparison results).