Complement activation and ADAMTS13 suppression may contribute to the characteristic pathological features in Upshaw-Schulman Syndrome - Complement activation and ADAMTS13 suppression in USS

Chronic glomerular sclerotic changes in the majority of USS cases (4 of 5), with minor glomerular pathology in the remaining case. In two of these four severe cases, more than half of the glomerular segmental sclerosis area was localized in the perihilar region. The average number of ADAMTS13-positive cells per glomerulus was significantly lower in USS cases than controls (p < 0.05). C4d staining was significantly more prevalent in the glomerular capillary walls of USS cases than controls (p < 0.05).