CCL4 and COVID-19: However, there is a strong correlation of various other chemokines [IL-8, CXCL-10 (IP-10), CCL-2 (MCP-1), CCL3 (MIP-1a) and CCL-4 (MIP-1b)] with severity of illness in critical COVID-19, and others [IL-6, IL-8, TNF-α, IL-1β, IL-6, IL-8 and sTNFR1] have been demonstrated to be associated with severe COVID-19, including the presence of organ system failure (Del Valle et al., 2020; Li et al., 2020; McElvaney et al., 2020; Anderberg et al., 2021; Kaiser et al., 2021; Khalil et al., 2021; Meizlish et al., 2021).