Complement activation associated with ADAMTS13 deficiency may contribute to the characteristic glomerular manifestations in Upshaw-Schulman syndrome

These findings suggest that the severity of glomerular injury in USS is associated with deficient ADAMTS13 expression and local complement activation, particularly in vascular regions with higher endothelial shear stress. We suggest that C4d immunostaining provides evidence for complement-mediated glomerular damage in USS.