IL17A and acute respiratory distress syndrome: Recent studies have confirmed that the content of Th17 cell-related factors and the ratio of Th17/Treg cells are increased in the alveolar lavage fluid of both clinical patients and experimental animals with ALI (21-, , 24), while the highly restrictive defect of Th17 cells, the deletion of IL-17 receptor, or the blocking of IL-17A antibody can significantly reduce ALI (25,26).