Figure 2

Histopathological examination by Periodic Acid Schiff reaction, x200. Glomeruli are characterized by widespread, intense mononuclear infiltration, moderate increase of the matrix and focal pericapsular fibrosis. Arteries show intense intimal fibrosis and fragmentation of the internal elastic lamina, arterioles are characterized by intense intimal hyalinosis. Edema and inflammatory infiltration of lymphocytes without plasmacells are present in the interstitium. Peritubular capillaries are markedly dilated with leucocytes margination. Epithelium of the proximal tubules occurs frequently flattened; into the lumen of the distal tubules, sometimes dilated, are contained hyaline casts. No nuclear inclusions are detected in the tubular epithelium. Search for C4d, evaluated by immunohistochemistry on tissue sections fixed, was positive (+ +) on the walls of peritubular capillaries.