Notably, despite the elevated level of circulating cytokines, substantial expression of proinflammatory cytokine genes was not detected in the peripheral monocytes, T cells or NK cells by single cell transcriptomic assay (Wilk et al., 2020), and impaired cytokine production by COVID-19 patient-derived peripheral myeloid cells and CD14+ monocytes in response to a viral TLR cocktail were confirmed in ex vivo cell culture experiments, regardless of the severity of COVID-19 donors (Arunachalam et al., 2020). Here, CD14 is linked to COVID-19.