TNF and COVID-19: Several studies found high levels of proinflammatory cytokines, such as interleukin (IL)-6, tumor necrosis factor (TNF)α, and interferon (IFN)γ, as well as T cell lymphopenia, decrease of non-classical (CD14loCD16hi) monocytes, and occurrence of neutrophil precursors in the peripheral blood of severe COVID-19 patients3–7.