TNFSF10 and viral infectious disease: Intriguingly, soluble TRAIL has been found in the bronchoalveolar lavage from patients with acute respiratory distress syndrome following viral infections [165, 166] and activation of the TRAIL/TRAIL-R pathway has been linked with alveolar epithelial cell death and consequent lung injury [166–168], suggesting that the immune response to viral infections involves the activation of the TRAIL/TRAIL-R system and that this needs to be tightly controlled to prevent damage.