CXCL1 and COVID-19: We previously reported that BAL fluid from these patients contained increased numbers of hyperactivated degranulating neutrophils and elevated concentrations of proinflammatory cytokines/chemokines (e.g., IL-1β, G-CSF, CXCL1, and CXCL8) compared with a non–COVID-19 viral pneumonia cohort of mechanically ventilated patients with influenza (29).