Fig. 1.

Immunohistopathology of TTP. VWF-rich hyaline thrombi are present in the arterioles and capillaries but not the venules of multiple organs of a patient that died of TTP due to ADAMTS13 inhibitors. The endothelial cells are intact and contain abundant granules of VWF. No inflammatory cell infiltration is noted. The renal glomeruli contain foci of microthrombi but have well preserved architectures, consistent with the patient’s hematuria and minimal Cr elevation (1.2 mg/dL) at the time of death. VWF is not expressed in the sinusoidal endothelial cells of the liver and no thrombi are detected in the hepatic sinusoids