IGFBP6 and acute respiratory distress syndrome: Among them, Tgm2 (transglutaminase 2), Anxa1 (annexin A1), Ankrd1 (ankyrin repeat domain 1), and F3 (coagulation factor III) existed in clusters 5 and 7 simultaneously and were considered marker genes of branch I. Compared with the control group, Gstm1 and Igfbp6 were upregulated in ARDS, while F3, Lgals1, Mgp, Tgm2, Ankrd1, and Anxa1 were downregulated (Figure 5D).