CXCL9 and COVID-19: Both non-resident macrophages and moMa in critical patients with COVID-19 showed a high expression of the chemokine encoding gene, CCL3 (Chua et al., 2020) The excessive release of the chemokine CXCL9 in patients with COVID-19 with severe clinical presentations was significantly higher compared with those of patients with mild and moderate clinical presentations (Jain et al., 2021).