TNF and acute respiratory distress syndrome: Tumor necrosis factor-α (TNF-α), an important proinflammatory factor of ALI/ARDS [3], stimulates the expression of intercellular adhesion molecule-1 (ICAM-1) and interleukin-8 (IL-8) in human pulmonary microvascular endothelial cells (HPMECs) [4–6].