To test this hypothesis, pulmonary hypertension (PH) was induced in C57Bl/6J, IL‐33 receptor gene deleted (ST2−/−) and MYD88 gene deleted (MYD88−/−) mice by exposure to 10% O2 and SU5416 injections (SUHX). This evidence concerns the gene IL1RL1 and pulmonary arterial hypertension.