TNF and COVID-19: Plenty of evidences indicate there exists strong cytokine storm in the COVID-19 patients, TNF-α and interleukins like IL-1β, IL-6, IL-8 are mainly secreted by the epithelial cells, endothelial cells, tissue macrophages and mast cells, the circulating levels of these cytokines increase acutely in COVID-19 patients (23, 24).