IL1RL1 and pulmonary fibrosis: A study has proved that in the absence of ST2, early, long-term, unresolved inflammation will occur, and IL-33 is an important pro-fibrotic cytokine, which signals through ST2, mainly through the recruitment of IL-6-dependent replacement-activated macrophages and guided pulmonary fibrosis, thereby promoting the occurrence and progression of pulmonary fibrosis (98).