KRT18 and COVID-19: Employing a single-cell RNA-Seq approach in bronchoalveolar lavage fluid (BALF) from patients with severe COVID-19, Liao et al. previously found that both AMΦ and newly recruited monocyte-derived MΦ are major drivers of local inflammation in the lung, similarly to what has been described in African green monkeys and in K18-hACE2-transgenic mice [48,58,59].