TGFB1 and pulmonary arterial hypertension: Median serum levels of immunoreactive TGF-1 beta were significantly higher in patients with Sch-PAH compared to patients without PAH (22496.9 [IR: 15936.7 – 32087.8] pg/ml versus 13629.9 [IR: 10192.2 – 22193.8] pg/ml) (p = 0.006).