Fig 2. Early segmental fibrinoid necrosis with early cellular crescent formation without endocapillary proliferation or evidence of immune complexes in the remaining glomerular tuft. This light microscopic finding is that of a pauci-immune necrotizing glomerulonephritis, with a specific diagnosis of anti-GBM antibody-mediated glomerulonephritis made by immunofluorescence (see Fig 3) (Jones silver stain; original magnification x400).