Histologic examples of TA-TMA affecting various organs. (A) Renal cortex with glomeruli showing thickened capillary walls and occluded vessel lumens. Red blood cell fragments can be seen (arrows) trapped in the mesangial matrix (H&E stain; magnification ×200). (B) Renal arteriole with separation of the endothelial cell layer from the arteriole wall with entrapped fragmented red blood cells (arrow). “Floating” endothelial cells (arrows) can be seen occluding the lumen of the vessel (H&E stain; magnification ×200). (C) Lung arteriole showing denuded endothelial layer with large fibrin thrombus trapping red blood cell fragments (H&E stain; magnification ×200). (D) Pulmonary arteriole with a recent thrombus and extravasated red blood cells (H&E stain; magnification ×200). (E-F) Mesenteric arterioles in the small bowel showing endothelial cell separation and red cell extravasation (H&E stain; magnification ×200). Nikon Eclipse 80i, 20×/0.75, Diagnostic Instruments 14.2 color mosaic, Spot software Version 4.6, Gimp 2.6.