TNF and acute respiratory distress syndrome: Various studies have demonstrated that ROS stimulates activation of innate immune cells and the subsequent release of inflammatory cytokines such as tumor necrosis factor (TNF)-ɑ and interleukin 6 (IL)-6, with evidence suggesting that ROS, together with inflammatory cytokines, can cause vascular endothelial dysfunction and further accelerate the progression of ALI including ARDS (8-10).