RETN and idiopathic pulmonary fibrosis: We also detect enrichment for neutrophil degranulation (Plac8, Itgam, Cybb, S100P, and Retn for IPF-1 and Chit1, Clec5a, Chi3l1 for IPF-3), consistent with the notion that neutrophils are among the first immune cells to be recruited for the site of inflammation [63].