XDH and acute respiratory distress syndrome: In rats with ALI induced by cytokines IL-1 and IFN-γ, lung inflammation and injury were involved in the activation of xanthine oxidoreductase (XOR) in newly recruited mononuclear phagocytes (MNP), and ROS produced by XOR in MNP exacerbated pulmonary inflammatory cell recruitment, oxidative stress, and alveolar cell apoptosis (Wright et al., 2004).