IL6 and chronic thromboembolic pulmonary hypertension: There is an obvious proinflammatory state in CTEPH, as described above, and significant upregulation in serum inflammatory mediators including IL-6, IL-8, IP-10, monokine induced by interferon-γ (MIG), macrophage inflammatory protein (MIP) 1α, and matrix metalloproteinase (MMP) 9 [23,65,66].