We observed that CD4+ T-cells from both bovine and humans exposed to conditioned media of IPAH/PH fibroblasts (CM -(h) PH Fibs) showed higher positivity of IFNγ whereas the positivity of IL10, IL4 and TGFβ was decreased compared with CD4+ T-cells in conditioned media of control fibroblasts (Figures 2A–D, left panel). Here, IL4 is linked to idiopathic pulmonary arterial hypertension.