Figure S3.

Human histopathology, related to Figure 2

(A) Representative micrographs of pan-microglial marker IBA1 immunostaining (brown) in the cerebral cortex (gray matter) or subcortical white matter of human subjects with or without COVID. Scale bars, 100 μm.

(B–E) Representative micrographs of lung tissue from human subjects with COVID.

(B) COVID Case #2 with no definite pneumonia or diffuse alveolar damage. Scale bar, 50 μm.

(C) COVID Case #3. Lung showing intra-alveolar fluid (^∗), and early hyaline membrane formation (arrows), indicative of acute alveolar damage (200× magnification).

(D) COVID Case #1. Lung showing diffuse alveolar damage including hyaline membranes (arrow), organizing pneumonia (^∗) and reactive pneumocytes (arrowhead). Scale bars, 50 μm.

(E) For comparison, an example of necrotizing COVID pneumonia (from a case not represented in this study) with alveolar spaces obliterated by significant infiltrative immune cells, chiefly neutrophils and macrophages. Vascular congestion present. Scale bars, 100 μm.