The distribution of each cluster in the selected 10 clusters was presented in Fig. 2B, and the results of cell cluster distribution grouped by control and PAH were displayed in Fig. 2C. Additionally, the number and proportion of cells in each sample were exhibited in Fig. 2D. In comparison with the control group, the proportion of adipocytes (39.4% vs. 5.6%) and fibroblasts (18.1% vs. 2.5%) was significantly reduced in the PAH group, while CD8+ T cell (3.3% vs. 50.0%) and macrophages (4.3% vs. 14.8%) were notably increased in PAH lung tissues compared with donors. This evidence concerns the gene CD8A and pulmonary arterial hypertension.