Several different histologic findings may be present in PIGN, and the diagnosis can usually be made using light microscopy and immunofluorescence. On light microscopy, PIGN classically causes diffuse hypercellularity involving all of the glomeruli, with the capillary lumina obscured by endothelial proliferation, mesangial proliferation, and infiltration by monocytes and neutrophils. Silver stain may reveal characteristic postinfectious humps in the subepithelial space. These humps represent deposits of immune complexes that include complement and immunoglobulins. Immunofluorescence usually shows granular deposition of C3 and IgG, and occasionally IgM. This staining may follow the capillary wall (“garland”) or it may be more diffuse (“starry sky.”) Electron microscopy will show large dome-shaped humps in the subepithelium, and it may also show small immune complexes in the mesan-gium and subendothelium.