In particular, macrophage-related cytokines like interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) were initially reported to be increased in COVID-19 infected patients compared with control subjects, with higher levels of cytokines in severe compared with non-severe infection (Chen et al., 2020; Huang et al., 2020; Ye et al., 2020). Here, IL6 is linked to COVID-19.