PMC9218267_01
Light microscopy showing prominent lobularization of glomeruli with both mesangial hypercellularity and endocapillary proliferation. Frequent glomerular inflammatory cells are also seen.
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F1
Light microscopy demonstrated a membranoproliferative pattern of glomerular injury including mesangial and endocapillary hypercellularity, inflammatory cell infiltration, and crescent formation (noted in 3 of 60 glomeruli visualized, see Figure 1).
Electron microscopy showing sub endothelial deposits (black arrows) as well as basement membrane duplication or "tram-tracking" (clear arrows).
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F2
Ultrastructural analysis demonstrated electron-dense deposits in the mesangium, paramesangium, and capillary loop basement membrane, with double contour of the glomerular basement membrane ("tram track pattern") on silver stain (see Figure 2).
Immunofluorescence showing 2+ IgA deposits (left) and 2+ C3 deposits (right) with granular capillary loop and mesangial staining.
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F3
Immunofluorescence revealed codominant C3 (2+) and IgA (2+) staining in the mesangium and capillary loops, and was negative for IgG, IgM, or C1q staining (see Figure 3).