According to our results, IPAH patients have higher levels of memory B-cells, CD8 T-cells, follicular helper T-cells, monocytes, and M1 and M2 macrophages and lower levels of plasma cells, memory resting CD4 T-cells, Tregs, resting NK cells, NK cells, resting mast cells, and eosinophils. Our results are consistent with those of previous studies. Here, CD4 is linked to idiopathic pulmonary arterial hypertension.