TNF and macrophage activation syndrome: Immune-mediated pulmonary injury or ARDS in Covid-19 results from dysregulated hypercytokinemia, the conditions called cytokine storm syndrome (CSS), secondary hemophagocytic lymphohistiocytosis (sHLH), or macrophage activation syndrome (MAS), characterized by increased plasma levels of interferon (IFN)-γ and proinflammatory cytokines, including interleukin (IL)-2 receptor, IL-6, IL-10, and tumor necrosis factor (TNF)-α [3,4,5].