TNF and COVID-19: Several proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL) 1β and chemotactic cytokines (e.g., IL-8 and macrophage chemoattractant protein-1 (MCP-1)) are upregulated during COVID-19, leading to a sustained increase in IL-6 levels [6,7,8,9,10].