Classic immunofluorescence features of ABBA. (a) IgG staining along TBMs and proximal tubular brush borders (fluorescein-conjugated anti-human IgG, original magnification 200x, scale bar = 50 μm). (b) IgG staining highlighting proximal tubular brush border and tubular epithelial cell cytoplasm (fluorescein-conjugated anti-human IgG, original magnification 400x, scale bar = 20 μm). (c) Granular IgG staining along TBMs and Bowman's capsule of a glomerulus (fluorescein-conjugated anti-human IgG, original magnification 200x, scale bar = 50 μm. (d) Segmental IgG staining along glomerular capillary loops and Bowman's capsule (fluorescein-conjugated anti-human IgG, original magnification 400x, scale bar = 20 μm). (e) LRP2 staining highlighting TBM deposits in addition to proximal tubular brush border staining (paraffin immunofluorescence staining for LRP2, original magnification 600x, scale bar = 20 μm). (f) Indirect immunofluorescence of ABBA sera demonstrates seroreactivity against the proximal tubular brush borders of normal human kidney (fluorescence conjugated anti-human IgG, original magnification 200x, scale bar = 50 μm).