Table 3.
Features of light microscopy and immunofluorescence (IF) studies of 22 kidney biopsies performed in 19 patients with myelodysplastic syndromes. Three patients underwent a repeat kidney biopsy
| Pt | Light microscopy |
Vessels | IF | Diagnosis | ||
|---|---|---|---|---|---|---|
| Glomeruli | Tubules | Interstitium | ||||
| 1 | 9 (4 sclerotic). Normal appearance. |
Rare atrophic tubules | Edema and diffuse (++) inflammatory cells infiltrate (mononuclear cells) | Normal | Mesangial IgA deposits (+/++) | Acute TIN |
| 2 | 22 (1 sclerotic) Normal appearance. |
Epithelial cell vacuolization. Exocytosis of inflammatory cells in tubular sections | Oedema and diffuse (+++) inflammatory cells infiltrate (lymphocytes and plasmocytes). Fibrosis < 10% | Mild arteriosclerosis | No significant deposits. | Acute TIN |
| 3 | 20 (9 sclerotic). Focal segmental lesions. Absence of proliferation. | Several tubular atrophy Focal tubulitis |
Inflammatory cell infiltrate (++/+++) (lymphocytes, plasmocytes, macrophages) in 30-40% of cortex area. Fibrosis 70% | Severe intimal fibrosis. Absence of thrombosis. | No significant deposits. | Acute TIN |
| 4 | 1st KB 20 (0 sclerotic). Normal appearance. |
Acute tubular necrosis | Oedema and inflammatory cells infiltrate (++/+++) (neutrophils, lymphocytes, plasmocytes) (including in peritubular capillaries) | Very mild arteriosclerosis | No glomeruli. | Acute TIN |
| 2nd KB (4 months later) 12 glomeruli (3 sclerotic). Normal appearance. |
No significant lesion | Regression of inflammatory cells infiltrate. Fibrosis 10% |
Very mild arteriosclerosis | No significant deposits. | ||
| 5 | 13 glomeruli (3 sclerotic). Absence of proliferation. Thickening of Bowman’s capsule (5 glomeruli). |
Deposits within the tubular basement membrane Acute injury in rare tubules |
Inflammatory cell infiltrate (++) (lymphocytes, plasmocytes, eosinophils) Multifocal fibrosis (50-60%) |
Moderate to severe arteriosclerosis | Polyclonal IgG (++/+++) deposits in Bowman’s capsule and TBM. Similar staining for IgG 1-4 subclasses. |
Acute TIN |
| 6 | 13 /2 (sclerotic). Mild mesangial proliferation (+). Focal segment lesions (2 glomeruli). |
Focal tubular atrophy | Inflammatory cell infiltrate (++) (lymphocytes/plasmocytes) in 30% of the cortical area. Fibrosis 60% | Mild intimal fibrosis | Mesangial IgA and C3 deposits (++). | Acute TIN. IgAN |
| 7 | 8 (2 sclerotic). Normal appearance. |
Mild tubular atrophy | Focal (+/++) inflammatory cell infiltrate (lymphocytes). Fibrosis 30-40% | Mild intimal fibrosis | No significant deposits. | Subacute/ Chronic TIN |
| 8 | 17 (0 sclerotic). Fibrinoid necrosis (3 glomeruli). Cellular or fibrocellular crescents (3 glomeruli). |
Tubular atrophy | Giant-cell granulomas Fibrosis 50% |
Normal | No significant deposits | PiNCG |
| 9 | 1st KB 12 (2 sclerotic). Fibrinoid necrosis (2 glomeruli). Glomerular infiltration by neutrophils. |
Rare atrophic tubules | Cortical inflammatory cell infiltrate (+/++) (neutrophils, lymphocytes, plasmocytes) Fibrosis 20% |
Mild intimal fibrosis | No significant deposits. | PiNCG |
| 2nd KB (10 months later). 10 glomeruli (2 sclerotic). Normal appearance. | Mild (+/++) tubular atrophy | Fibrosis 30-40% | Normal | No significant deposits. | ||
| 10 | 11 (1 slerotic). Cellular crescents (3 glomeruli). Intra-glomerular inflammatory cells. Segmental aspects of TMA. |
Mild (+) tubular injury | Inflammatory cell infiltrate (+/++) (lymphocytes and plasmocytes) | Severe arteriosclerosis | No significant deposits. | PiNCG |
| 11 | 1st KB 22 (1 sclerotic). Stiffness of the capillary walls. Absence of proliferation. |
Normal | Normal | Mild intimal fibrosis | Granular IgG (+++), C3 (+++) and IgM (+) along the capillary walls. Negative PLA2R1 staining. | MN |
| 2nd KB (6 months later). 19 (1 sclerotic). Thickening of the capillary walls. Presence of inflammatory cells (lymphocytes, monocytes, neutrophils) in capillaries. |
Mild atrophy | Mild to severe fibrosis Moderate (+/++) inflammatory cell infiltrate (lymphocytes) |
Mild intimal fibrosis | Granular IgG (+++), C3 (+++) along the capillary walls. Positive PLA2R1staining. |
||
| 12 | 10 (0 sclerotic). Deposits and spikes along the basement membrane. |
Mild tubular atrophy | Mild fibrosis | Mild arteriosclerosis | Parietal granular polyclonal IgG (+++) deposits. | MN |
| 13 | 9 glomeruli (0 sclerotic). Mild mesangial proliferation (+/++). | Normal | Fibrosis < 20% | Mild arteriosclerosis | Mesangial and parietal IgA (++), fibrin (++) and C3 (+) deposits. | IgA vasculitis |
| 14 | 7 (2 sclerotic). Mild (+) mesangial matrix expansion. Focal segmental lesion (1 glomerulus). |
Mild tubular atrophy | Fibrosis < 10% | Mild arteriosclerosis | Parietal IgA (++) deposits. | IgAN. |
| 15 | 8 glomeruli (1 sclerotic). Mesangial deposits. Absence of proliferation. |
Mild acute tubular lesions | Mild (+/++) inflammatory cell infiltrate (lymphocytes, plasmocytes) | Fibrosis < 10% | Mesangial and intra-membranous IgG (+++) and C3 (++) deposits.∗ | Ig- MPGN |
| 16 | 20 (3 sclerotic) Focal mesangial cell proliferation (+/++). Cellular crescents (3 glomeruli). | Acute tubular necrosis | Diffuse (++) interstitial inflammatory cell infiltrate (lymphocytes, plasmocytes) Fibrosis 10% |
Mild intimal fibrosis | Mesangial and parietal C3 (+++) deposits. | Crescentic C3G. Acute TIN. |
| 17 | 11 (4 sclerotic). Mesangial matrix expansion and mild hypercellularity (+). Parietal deposits. Cellular crescent (1 glomerulus) and focal segmental lesions (4 glomeruli). |
Mild atrophy | Mild fibrosis | Normal | Polyclonal IgG (+++) parietal deposits. IgG1++, IgG2-, IgG3-, IgG4+/++. ∗∗ |
Fibrillary GN. |
| 18 | 10 (1 sclerotic). | Rare atrophic tubules | Fiibrosis < 10% | Intimal fibrosis | No significant deposits | MCD. |
| 19 | 9 (0 sclerotic). | Normal | Fibrosis < 10% | Normal | No significant deposits. | Normal |
C3G, C3 glomerulopathy; IgAN, IgA nephropathy; IgG GN, IgG glomerulonephritis; Ig-MPGN, immunoglobulin-mediated membrano-proliferative glomerulonephritis; KB, kidney biopsy; MCD, minimal change disease; MN, membranous nephropathy; PiNCG, pauci-immune necrotizing and crescentic glomerulonephritis; Pt, patient; TBM, tubular basement membrane; TIN, tubulo-interstitial nephritis.
∗
Electron microscopy study disclosed the presence of glomerular non-dense deposits
∗∗
Congo red staining was negative. Electron microscopy study disclosed the presence of glomerular deposits composed of randomly oriented fibrils of 12 ± 1.2 nm (mean ± standard deviation of 10 random measurements) in external diameter without distinct hollow core. Gold particles labelling anti-DNAJB9 (a specific marker of fibrillary glomerulonephritis) bound the fibrils.