Additionally, agonistic autoantibodies against platelet-derived growth factor receptor (PDGFR), angiotensin II type 1 receptor (AT1R), and endothelin A receptor (ETaR) have been implicated in the further activation of fibroblasts and immune cells, correlating with severe SSc complications such as ILD and PAH. The gene discussed is AGTR1; the disease is systemic sclerosis.