TNF and macrophage activation syndrome: Hyperinflammation similar to macrophage activation syndrome has been detected in patients with severe COVID-19, including massively increased production of cytokines, such as IL-6, IL-7, and tumor necrosis factor (TNF), and of inflammatory chemokines, such as CC-chemokine ligand 2 (CCL2), CCL3, and CXCL10 (Schulert and Grom, 2015; Mehta et al., 2020).