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). The gene discussed is FCGR1A; the disease is pulmonary arterial hypertension.