The prevalence of Th2 (CD4+ IL-4+/CD4+ T cells) in peripheral blood was higher in ALI 24 h group than that in ALI 6 h group (ALI 6 h group: 10.2 ± 0.9%, ALI 24 h group: 12 ± 0.68%, P = 0.067, Supplementary Fig. S2). This evidence concerns the gene CD4 and acute respiratory distress syndrome.