CD14 and COVID-19: More importantly, multiple pro-inflammatory cytokines and chemokines were highly expressed by the BALF monocyte–macrophages, suggesting that the cells are inflamed.64 Another single-cell sequencing analysis of peripheral blood samples also showed that CD16+ monocytes were remarkably depleted in COVID-19 patients with ARDS, with a phenotypic shift from CD16+ to CD14+.