Fig. 6: Pancreatic infection pattern in COVID-19 deceased patients.
From: SARS-CoV-2 infects and replicates in cells of the human endocrine and exocrine pancreas
a, Pancreatic tissue sections from four different COVID-19 deceased patients stained for SARS-CoV-2 N protein (red) and insulin (brown). Rectangles mark areas of higher magnification in the next row. Insets show further high magnification to illustrate specific patterns. Asterisks mark the magnification of stained areas outside the illustrated regions but corresponding to the patients from the respective column. Infection occurred as N-positive clusters in all four patients with positivity of some ductal cells and a few acinar cells. Insulin and N-protein double-positive cells were observed in three out of four patients (marked with a hash). A representative image from one biopsy section of each patient is displayed. b, N-positive cells are often located in close vicinity to the islets of Langerhans or even mixed in islet-like structures together with insulin-positive cells. The morphology of N-positive cells frequently resembled non-acinar/non-ductal morphology. A representative image is derived from one biopsy section of patient 1. c, Vicinity ratio of N-positive regions (>5 positive cells) located near insulin-positive endocrine cells (<100-µm distance to endocrine cell) divided by all N-positive regions (>5 positive cells) reveals that SARS-CoV-2 is not randomly distributed across the pancreas, but rather located close to endocrine structures. On average, 51% of N-positive regions are located close to endocrine cells or islets. For statistical testing, two-sided Fisher’s exact test was applied to the absolute numbers (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001). d, Viral N- and insulin-double-positive cells are rare (arrowheads) but interlaced into the islets of Langerhans. The highest N-protein signal in a cell cluster or even in individual cells correlates with the lowest insulin signal (close-up). e,f, Consecutive sections were stained for either insulin (e) or NKX6.1 (f), together with N protein. Rectangles in (i) mark areas of higher magnification (ii). Dashed areas connected with double-headed arrows mark corresponding regions that are highly N positive, insulin negative and NKX6.1 positive (left) or N negative, insulin positive and NKX6.1 positive (right). Representative images are derived from one biopsy section of patient 2. Scale bars, 100 µm; insets, 10 µm.
