MESANGIAL INVOLVEMENT IN HEMOLYTIC-UREMIC SYNDROME - LIGHT AND ELECTRON-MICROSCOPIC STUDY

Abstract

EM analysis was performed in 10 patients. Proteinaceous material similar to that found in the subendothelial region was seen focally in the mesangium altering the matrix and imparting a reticular appearance. This degeneration was associated with reparative changes in the glomerular tuft. Many of the mesangial cells were hypertrophied and showed phagocytic activity and peripheral extension of their cytoplasmic processes. Mitotic figures in endothelial and mesangial cells were evidence of a reparative process. Severe mesangial insudation of material containing fibrinogen derivatives resulted in segmental tuft necrosis with almost complete replacement and destruction of the mesangial matrix. A break of the glomerular basement membrane and escape of intraluminal contents into the urinary space, leading to crescentic epithelial cell proliferation was seen.