MPO and COVID-19: Accordingly, neutrophil counts, serum cytokines (IL-6 and IL-8), lipopolysaccharide (LPS), bacteria-free DNA, and NETs parameters (fluorescent-stained nuclear morphology, dsDNA, neutrophil elastase, histone–DNA complex, and myeloperoxidase–DNA complex) were found to differentiate COVID-19 severity, whereas serum (1→3)-β-D-glucan (BG) was different between the control and COVID-19 cases.