Fig. 1

Kidney biopsy findings. a Light microscopy findings in a paraffin-embedded section. Diffuse mesangial proliferation, thick glomerular basement membranes (GBMs) and double contours of the GBMs (thin arrow) with mesangial interposition (thick arrow) are observed (periodic acid-silver methenamine staining, magnification 400×). b-c Immunofluorescence images, showing granular staining for IgG and C3 in the mesangial area and capillary walls. d-e Electron micrography images, showing marked subendothelial electron-dense deposits, including hump-shaped subepithelial deposits (magnification 6000×). f Absence of mesangial proliferation and GBM thickening (periodic acid-Schiff staining, magnification 400×)