CD8A and pulmonary arterial hypertension: In the PAH dataset, immune cell correlations among the 22 immune cell types showed that M2 macrophages, CD8+ T cells, resting dendritic cells, and resting mast cells were predominantly positively correlated, while negative correlations with activated natural killer cells, M0 macrophages, eosinophils, activated dendritic cells, plasma cells, and regulatory T cells were observed (Supplementary Figures S6B, C).