EDNRB and pulmonary arterial hypertension: A recent study on ETBR immunodynamics highlighted the presence of a regulatory feedback of the effect of ET-1 on immune cells: ETBR deficiency in engineered mice led to PAH, pulmonary vascular hyperresponsiveness and right ventricular hypertrophy with lymphocytic alveolitis and marked lymphocytic perivascular infiltrate, suggesting that ETBR-mediated signalling pathways may have an immunomodulatory effect [31].