Electron microscopy in type I membranoproliferative glomerulonephritis

Electron micrograph in type I membranoproliferative glomerulonephritis shows marked thickening of the glomerular capillary wall by immune deposits (arrowhead) and by interposition of mesangial cell processes (arrow). There are two layers of the glomerular basement membrane (GBM) surrounding the mesangial interposition that account for the double-contour appearance on light microscopy.

Electron micrograph of a normal glomerular capillary loop showing the fenestrated endothelial cell (Endo), the glomerular basement membrane (GBM), and the epithelial cells with its interdigitating foot processes (arrow). The GBM is thin, and no electron-dense deposits are present. Two normal platelets are seen in the capillary lumen.