Analysis of pathological changes in the epithelium in COVID-19 patient airways

Coronavirus disease 2019 (COVID-19) patient lungs exhibit mucus plugs and pathological changes in the airway epithelium. Chest radiographs obtained on a) 12 January 2020, b) 17 January 2020 and c) 22 January 2020. d, e) Representative lung CT image on 13 January 2020. f, g) Representative transverse lung CT image on 23 January 2020. Chest radiographs obtained on h) 30 January 2020 i) 1 February 2020 and j) 15 February 2020. k) Representative images of lung tissue sections from the COVID-19 patient stained with haematoxylin and eosin (HE). Asterisks indicate airways. l) Representative images of lung tissue sections from the COVID-19 patient stained with periodic acid–Schiff (PAS). The arrows point to goblet cells. Asterisks indicate mucus plugs in the airways. m) Immunostaining for MUC5AC (green) and DAPI staining (blue) of sections of larger distal bronchioles from healthy controls (n=3) and the COVID-19 patient. The arrow points to the mucus plug. The arrowhead points to the goblet cell. n) Quantification of the number of larger distal bronchioles plugged by mucus in healthy controls (n=3) and the COVID-19 patient. o) Quantification of the number of larger distal bronchioles with MUC5AC⁺ cells in healthy controls (n=3) and the COVID-19 patient. p) Immunostaining for MUC5AC (green) and DAPI staining (blue) of sections of the smaller distal bronchioles from healthy controls (n=3) and the COVID-19 patient. The arrow points to the mucus plug. The arrowhead points to the goblet cell. q) Quantification of the number of smaller distal bronchioles plugged by mucus in healthy controls (n=3) and the COVID-19 patient. r) Quantification of the number of smaller distal bronchioles with MCU5AC⁺ cells in healthy controls (n=3) and the COVID-19 patient. s) Relative MUC5AC mRNA levels in the lungs from healthy controls and the COVID-19 patient. t) Immunostaining for MUC5B (red) and DAPI staining (blue) of sections of the airways from healthy controls (n=3) and the COVID-19 patient. u) Quantification of mean fluorescence intensity of MUC5B immunostaining in the airways in healthy controls (n=3) and the COVID-19 patient. v) Relative MUC5B mRNA levels in the lungs from healthy controls and the COVID-19 patient. w) Immunostaining for acetylated α-tubulin (green) and DAPI staining (blue) of sections of small bronchioles from healthy controls (n=3) and the COVID-19 patient. x) Quantification of the relative number of acetylated α-tubulin⁺ multiciliated cells in small bronchioles in healthy controls (n=3) and the COVID-19 patient. y) Immunostaining for CC16 (red) and DAPI staining (blue) of sections of distal bronchioles from healthy controls (n=3) and the COVID-19 patient. z) Quantification of the relative number of CC16⁺ cells in distal bronchioles in healthy controls (n=3) and the COVID-19 patient. aa) Relative CC16 mRNA levels in the lungs from healthy controls and the COVID-19 patient. bb) Quantification of CC16 levels in serum from healthy controls (n=7) and severe and critical COVID-19 patients (n=9). cc) Immunostaining for interleukin (IL)-13 (red) and DAPI staining (blue) of sections of the lungs from healthy controls (n=3) and the COVID-19 patient. dd) Quantification of mean fluorescence intensity of IL-13 immunostaining in the lungs in healthy controls (n=3) and the COVID-19 patient. ee) Representative images of cross sections of air–liquid interface (ALI) cultures stained with HE. The arrow points to cilia. ff) Trans-epithelial electrical resistance (TEER) measurements. gg) Immunostaining for MUC5AC (red), severe acute respiratory syndrome coronavirus 2 nucleocapsid proteins (SARS-CoV-2 N; green) and DAPI staining (blue) in human bronchial epithelial cells at the ALI after a 14-day differentiation. Scale bars: 100 μm (k, l, m, p, gg), 20 μm (t, w, y, cc, ee). *: p<0.05; **: p<0.01; ***: p<0.001; ****: p <0.0001; unpaired t-test, mean±sd.