Subendothelial deposits in mixed cryoglobulinemia

Electron micrograph in mixed cryoglobulinemia shows subendothelial deposits (D) under the glomerular basement membrane (GBM) with some of the granular material present within an infiltrating macrophage (arrows). The latter represents a phagocytic process that would remove the cryoprecipitate if no further deposition occurred.

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.