Immunosuppressant-induced endothelial damage and pulmonary arterial hypertension.

Cyclosporine A, used to prevent graft-versus-host-disease, is known to induce endothelial injury. Endothelial dysfunction is an important feature of pulmonary arterial hypertension (PAH). In this article, we describe 2 children who developed cyclosporine-induced acute respiratory distress syndrome. Lung biopsy showed patchy loss of endothelial caveolin-1 and von Willebrand factor to occur early. Significant loss of endothelial caveolin-1 was associated with robust expression of caveolin-1 in smooth muscle cells with subsequent neointima formation leading to fatal PAH. Thus, patients who develop acute respiratory distress syndrome after immunosuppressive therapy are at risk of developing PAH.