Inflammation in pulmonary hypertension: what we know and what we could logically and safely target first.

Inflammation is important for the initiation and the maintenance of vascular remodeling in most of the animal models of pulmonary arterial hypertension (PAH), and therapeutic targeting of inflammation in these models blocks PAH development. In humans, pulmonary vascular lesions of PAH are the source of cytokine and chemokine production, related to inflammatory cell recruitment and lymphoid neogenesis. Circulating autoantibodies to endothelial cells and to fibroblasts have been reported in 10-40% of patients with idiopathic PAH, suggesting a possible role for autoimmunity in the pathogenesis of pulmonary vascular lesions. Current specific PAH treatments have immunomodulatory properties, and some studies have demonstrated a correlation between levels of circulating inflammatory mediators and patient survival. New immunopathological approaches to PAH should enable the development of innovative treatments for this severe condition.