Fig. 1 Alloimmune-mediated rejection causes microhemorrhage in airway transplants. Alloimmune-mediated rejection causes microhemorrhage in airway transplants. Comparison of allotransplants and syntransplants (n = 3 to 6 per group) by day posttransplant for (A) mean blood perfusion units measured by Doppler flowmetry and (B) fluorescein isothiocyanate (FITC)–conjugated lectin perfusion. a.u., arbitrary units. (B) Microbeads (yellow arrows) are extravasated (red) or colocalized (yellow) with microvascular FITC-lectin staining (green). Magnification, ×10. Scale bar, 100 μm. (C) Mean percent area perfused in the tracheal transplant model. (D) Microbead density area, measured by the percentage of the tracheal transplant with extravasated fluorescent microbeads. Data are means ± SEM and analyzed by Student’s t test. (E) Transmission electron micrograph of transplanted mouse trachea depicts vascular intimal layer (dashed red ellipse) with erythrocyte collections (yellow asterisks). The white arrow indicates an extravasating erythrocyte. Magnification, ×4500. (F) Tissue oxygen tension (PO2, mmHg) by day posttransplant in allotransplants and syntransplants (n = 3 to 6 per group) measured by Oxyprobe. Data are means ± SEM and analyzed by Student’s t test. Joe L. Hsu et al., Sci Transl Med 2018;10:eaag2616 Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works