TNFSF10 and pulmonary arterial hypertension: Our analysis revealed IFI44 (IFN inducible protein 44) as the only significantly upregulated gene in the small intestine and the lungs of mice on a 15-HETE diet and in the lungs of PAH patients. Furthermore, we demonstrate that CD8 cells upregulate IFI44 and its target TRAIL and promote PH by decreasing the pulmonary vascular bed density.