Fig. 1

Histopathological findings on the first renal biopsy. a and b Particle-like deposition of IgG and C3, along the capillary wall (immunofluorescence assay). c No specific lesions in the renal interstitium (light microscopy: hematoxylin and eosin (HE), × 200). d and e Diffuse thickening of the glomerular basement membrane, subepithelial deposition of fuchsinophilic protein, and segmental spike formation (light microscopy: Masson and periodic acid-sliver methenamine(PASM), × 400). f Diffuse and irregular thickening of electron-dense deposits in the subepithelial, intrabasal, and mesangial areas and diffuse fusion of the foot processes among epithelial cells; however, no specific lesions were seen in renal tubules or interstitium. Red Arrow: electron-dense deposits; Blue arrow: diffuse fusion of the foot processes among epithelial cells (electron microscopy, × 6000)