IL6 and pulmonary arterial hypertension: Previous studies suggested that the lungs from PAH patients are characterized by the infiltration of inflammatory cells and an increase in pro-inflammatory cytokines, such as interleukin-1 alpha (IL-1α), interleukin-1 beta (IL-1β), platelet derived growth factors beta polypeptide b (PDGF-BB), interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), and tumor necrosis factor-alpha (TNF-α) [6–9].