In hypoxia-induced PAH mice, IL-33, a member of the IL-1 family of cytokines, binds to the membrane receptors ST2, and initiates pulmonary vascular remodeling by upregulating the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) (Liu et al., 2018). Here, IL1B is linked to pulmonary arterial hypertension.