IL17A and acute respiratory distress syndrome: The prevalence of Th17 (CD4+ IL-17A+/CD4+ T cells) in lung was significantly higher in ALI 24 h group than that in normal control group (Con group: 0.8 ± 0.09%, ALI 24 h group: 2.7 ± 0.17%, P < 0.0001, Fig. 4).