CXCL5 and COVID-19: The 10- to 100-fold higher levels of the most potent human neutrophil-attracting chemokine, CXCL8, and the neutrophil-attracting chemokines CXCL1 and CXCL5 in the BAL fluid of COVID-19 versus influenza patients could explain the major neutrophil infiltration in the lungs.