One of the first studies to evaluate the serum cytokine storm in COVID-19 patients showed that several pro-inflammatory mediator levels, such as TNFα, IL-2, IL-7, IL-10, G-CSF, CXCL10, CCL2 and CCL3, were increased in ICU (n = 13) compared to non-ICU COVID-19 patients (n = 28) [184]. Here, TNF is linked to COVID-19.