Figure 5. Neutrophil influx, and NETosis in the lung parenchyma
of COVID-19 lung autopsy cases.
(A) H&E staining of lung tissues with massive neutrophil influx. (B)
Neutrophils show high expression of neutrophil elastase. (C) Insert from
panel B depicts extracellular release of NE (white asterisk) in the
alveoli. (D) Lung sections with immunohistochemistry for MPO also
indicate neutrophil activation. (E) PAD4 staining. (F) Increased levels
of total citrullinated proteins in the lungs of COVID-19 patients
compared to COVID-19-negative patients. Scale Bar=100 μm.