IL1RL1 and pulmonary fibrosis: Unexpectedly, it was found that acute neutrophilic lung inflammation led to the development of IL-33/ST2-dependent pulmonary fibrosis associated with M2-like polarization production, and that 24 hours after bleomycin treatment, ST2-deficient mice exhibited enhanced inflammatory cell recruitment, and MRI showed enhanced inflammation in the lungs with pulmonary edema (91).