IFN-γ, granzyme B, IL-6, IL-10, IL-15, IL-18, CCL2, CCL3, CCL4, CCL8, CXCL5, and CXCL10 levels were not significantly different from levels in BAL fluid of patients with influenza, although a tendency toward increased concentrations was seen in the patients with COVID-19. Here, CCL4 is linked to COVID-19.