IL6 and pulmonary arterial hypertension: Inflammatory cytokines such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) are elevated in PAH, contributing to endothelial damage and vascular remodeling (Steiner et al., 2009; El Chami and Hassoun, 2012; Groth et al., 2014).