In the present study, the serum levels of ET‐1 and IL‐6 in the IPAH cohort were also significantly higher than those in control groups (Appendix Fig S1A and B) with areas under the ROC curve 0.74 and 0.74, respectively (Appendix Fig S1C and D). Here, IL6 is linked to idiopathic pulmonary arterial hypertension.