TNF and acute respiratory distress syndrome: Pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukins 1 and 6 (IL-1 and IL-6) increase permeability in the host’s vascular system by the dilation of smooth muscle and the contraction of the endothelial cells of blood vessels, which leads to alveolar edema and alveolar collapse, thereby leading to refractory hypoxemia and finally ARDS.