CXCL1 and pneumonia: Arguing against an unusually severe inflammatory response or “cytokine storm” in patients with COVID-19, the concentrations of other BAL fluid cytokines in samples collected during the first 48 hours of intubation, including CXCL1, IFN-γ, IL-1β, IL-6, IL-8, and TNF-α, were higher in patients with pneumonia relative to healthy controls but were largely similar between groups of mechanically ventilated patients (complete comparisons are included in Supplemental Data 7).