PMC3482065_01
A, B Histology of the native kidney. The glomeruli show segmental cellular crescent (A, B) and diffuse endocapillary hypercellularity (B). C, D Histology of the graft (first biopsy). The glomeruli show the same pattern found on the native kidneys with extracapillary proliferation (C) and endocapillary proliferation (D; periodic acid-Schiff; original magnification x400). E IF performed on the graft (first biopsy) shows a strong granular capillary staining of the glomerulus in the mesangium and in the subendothelial sites (IgG, original magnification x400). F A similar pattern was found on the native kidney (single light-chain isotype kappa, original magnification x400). G Electron microscopy from the first transplant biopsy shows large granular subendothelial electron-dense deposits (original magnification x5,200). H Electron microscopy of the native kidney shows the same pattern with subendothelial and mesangial electron-dense deposits (original magnification x3,000).
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F1
ANA and Abs anti-dsDNA were negative, cryoglobulins were absent, and C3 was low. A renal biopsy revealed an unclassifiable endocapillary proliferative GN with cellular crescents (16/27 glomeruli; fig. 1a, b) and global sclerosis (3/27 glomeruli) associated with inflammatory infiltrate of the interstitium. IF patterns documented on native kidneys (fig. 1c-e). In addition, a positive IF staining for single light-chain isotype kappa and the presence of large finely granular electron-dense deposits without structure on electron microscopy were detected (fig. 1g). A retrospective study of the native kidney biopsy showed identical IF positivity for single light-chain isotype kappa (fig. 1f) and the same electron microscopy finding with large mesangial and parietal electron-dense deposits (fig. 1h).
A, B Histology of the graft (second biopsy) after plasmapheresis treatment show less disease activity. The glomeruli show only a segmental mesangial hypercellularity (periodic acid-Schiff; original magnification x400). C, D IF performed on the graft (second biopsy) displays only a slightly segmental mesangial staining of the glomerulus (IgG, original magnification x400).E, F Representative images of the histology of the graft after transplant nephrectomy showing one normal glomerulus and one with mesangial hypercellularity (E), and one glomerulus with segmental cellular crescent (F; periodic acid-Schiff; original magnification x400).
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F2
A protocol biopsy performed 3 months later showed a focal and segmental mesangial proliferation with disappearance of the endocapillary proliferation and cellular crescents (fig. 2a, b). Nevertheless, IF staining for IgG, C3, C1q and single light-chain isotype kappa remained positive only in the mesangium (fig. 2c, d). Unexpectedly, the histology of the graft displayed a large number of normal glomeruli and only few glomeruli (4%) with a low degree of mesangial and/or extracapillary proliferation without signs of acute rejection (fig. 2e, f).