CCL4 and chronic thromboembolic pulmonary hypertension: Compared with the IPAH population, IL-1B, CXCL8, CCL22, CCL5, CCL20, TNF, IL-12B, JUN, and CCL4 were highly expressed in CTEPH patients, suggesting that the above nine characterized genes were expressed higher in CTEPH disease than in IPAH patients; the opposite was true for EP300 (Fig 5A).