Fig. 4

Immune signature of thrombi of COVID-19 and control stroke patients. A to F. Characterization of the thrombus immune cell signature of thrombi retrieved from COVID-19 and control stroke patients. A. Neutrophil number (MPO⁺ cells) and representative images of a thrombus of a COVID-19 and control patient with MPO immunohistochemical staining (in brown; p = 0.04, Mann Whitney). B. NET content (CitH3⁺ area) and representative images of thrombi with citH3 immunohistochemical staining (in brown; % of citH3⁺ area out of total thrombus area in COVID-19 patients and controls respectively, median [IQR]; p = 0.19, Mann Whitney). C. T and B cells (CD3+ and CD20+ cells) number and representative images of thrombi with CD3 (in brown) and CD20 (in blue) immunohistochemical staining of COVID-19 and control stroke patients; p = 0.11, median [IQR], Mann Whitney). D. Histogram representing the thrombus neutrophil-to-lymphocyte ratio (tNLR, in COVID-19 and control patients; p ≤ 0.01, Mann Whitney). E. Macrophages (CD68 PGM1⁺ cells) and representative images of thrombi with CD68-PGM1 immunohistochemical staining (in brown; p = 0.12, Mann Whitney). F. Quantification of complement (C5b-C9⁺ area) and representative images of thrombi with C5b-C9 immunohistochemical staining (in brown). Scale bar inA–F, 100 μm. In the scatter plots each dot corresponds to the thrombus of one patient (n = 7 COVID-19 and n = 23 control patients)