We have done a literature search using the following terms: (“idiopathic pulmonary fibrosis” OR “IPF” OR “lung fibrosis”) and (TSLP or “thymic stromal lymphopoietin” or IL‐25 OR IL‐17E OR IL‐33) from the database of PubMed published in English up to July 2018. Here, IL25 is linked to pulmonary fibrosis.