Patients with PAH had a lower ETB surface expression on monocytes when compared to patients without PAH, although the difference was not statistically significant (77.2 ± 23.4 versus 96.9 ± 27.3); this difference was significant when considering patients with the limited subset of the disease (77.6 ± 17.6 versus 102.3 ± 24.4; P < 0.05) (Table 2). This evidence concerns the gene EDNRB and pulmonary arterial hypertension.