PI3 and acute respiratory distress syndrome: Peptidase inhibitor 3 (PI3), C-X3-C motif chemokine receptor 1 (CX3CR1) and FYN proto-oncogene, Src family tyrosine kinase (FYN) have been confirmed to be related to the pathogenesis of inflammation or immunity, endothelial function, epithelial function, and coagulation function in both ARDS animal models and in vitro experiments.