CD4 and idiopathic pulmonary arterial hypertension: Between the last groups of patients, i.e., CTEP and IPAH, we recorded six common coalescences, namely mean pressure in the right ventricle and IL-2 concentration (negative); CD4+ and CD4+/CD8+ (positive); CD3+ and CD8+ (positive); CO and Cl (positive); PASP and RVSP (positive); and CD4+ and CD8+, which was positive in IPAH patients and negative in CTEPH patients.