IL4 and idiopathic pulmonary fibrosis: In addition to the ECM of IPF patients, TGF-β, endothelin, CTGF, interleukins (IL-3 and IL-4), serum response factors (Shi-Wen et al., 2004) and microRNA (miRNA-21, miRNA-22, miRNA-29, miRNA-125b, miRNA-126, miRNA-130a and miRNA-132, miRNA-142a) (Pandit et al., 2011; Wang et al., 2012; Cushing et al., 2015; Kuse et al., 2020) have been shown to be associated with the differentiation of fibrocytes into fibroblasts.