IL6 and viral infectious disease: Reactive oxygen species (ROS) produced during radiotherapy activate nuclear transcription factor NF-κB (nuclear factor kappa B), proinflammatory cytokines (such as tumor necrosis factor-α and interleukin-6) and metabolic byproducts that promote apoptosis, aggravate tissue damage, cause bacterial, fungal, and viral infections, and aggravate radiochemotherapy-induced oral mucositis in patients with NPC.11,12