The vioplot of the immune cell infiltration difference demonstrated that IPAH patients had a higher level of CD8+ T cells, resting memory CD4+ T cells, gamma delta T cells, M1 macrophages, resting mast cells, and a lower level of naïve CD4+ T cells, monocytes, M0 macrophages, activated mast cells, and neutrophils compared with the control group (Figure 7C). This evidence concerns the gene CD4 and idiopathic pulmonary arterial hypertension.