CXCL12 and pulmonary arterial hypertension: In a rat model of MCT‐induced pulmonary arterial hypertension (PAH), MCT treatment induced perivascular infiltration of macrophages, mast cells and T cells which was reduced by inhibiting CXCL12, which is a key homeostatic chemokine that controls leukocyte migration into a range of tissues including the lung.47