Table 2.
Overview of histopathologic findings (N = 73 biopsies from 67 patients)
| Pathologic finding | Value |
|---|---|
| Light microscopy | |
| No. of glomeruli (mean ± SD) | 17.8 ± 14.2 |
| Percent globally sclerotic glomeruli (mean ± SD) | 26.3 ± 19.0 |
| Cases with segmental GBM holes via Jones silver stain, n (%) | 41 (56.2%) |
| Acute tubular injury, n (%) | 70 (95.9%) |
| Interstitial edema, n (%) | 49 (67.1%) |
| Tubulitis, n (%) | 19 (26.0%) |
| Interstitial inflammation (N = 70): none/mild/moderate/severe | none 25/70 (35.7%), mild 24/70 (34.3%), moderate 15/70 (21.4%), severe 6/70 (8.6%) |
| Increased Interstitial IgG4 cells, n (%) >10 IgG4+ plasma cells/high power field |
4 (5.4%) |
| Tubular atrophy: none/mild/moderate/severe | none 4/72 (5.6%), mild 21/72 (29.2%), moderate 33/72 (45.8%), severe 13/72 (18.1%) |
| Interstitial fibrosis: none/mild/moderate/severe | none 6/72 (8.3%), mild 19/72 (26.4%), moderate 32/72 (44.4%), severe 15/72 (20.8%) |
| Immunofluorescence | |
| IgG along proximal tubular brush borders, n (%) | 56/73 (76.7%) |
| IgG granular staining along TBMs, n (%) | 72/73 (98.6%) |
| C3 granular staining along TBMs, n (%) | 47/73 (64.3%) |
| IgG in interstitium, n (%) | 1/73 (1.4%) |
| IgG granular staining along capillary loops, n (%)a | 57/72 (79.2%) |
| Segmental (<50%) | 53/72 (73.6%) |
| Global (≥50%) | 4/72 (5.6%) |
| C3 granular staining along capillary loops, n (%)a | 34/72 (47.2%) |
| IgG staining along Bowman's capsule, n (%)a | 52/72 (72.2%) |
| Segmental (<50%) | 27/49 (55.1%) |
| Global (≥50%) | 22/49 (44.9%) |
| LRP2 immunofluorescence TBM positivity, n (%)a | 65/69 (94.2%) |
| IgG1 staining; dominance (strongest intensity) | 44/49 (89.8%); 20/49 (40.8%) |
| IgG2 staining; dominance | 7/49 (14.3%); 0/49 (0%) |
| IgG3 staining; dominance | 1/49 (2.0%); 0/49 (0%) |
| IgG4 staining; dominance | 42/49 (85.7%); 12/49 (24.5%) |
| IgG1 and IgG4 co-dominance | 17/49 (34.7%) |
| Electron microscopy (N = 63) | |
| Tubular basement membrane deposits, n (%)b | 55 (87.3%) |
| Subepithelial electron-dense deposits, n (%)b | 44 (69.8%) |
| Subendothelial electron-dense deposits, n (%)b | 2 (3.2%) |
| Mesangial deposits, n (%)b | 19 (30.2%) |
GBM, glomerular basement membrane; SD, standard deviation; TBMs, tubular basement membranes.
a
One case did not have glomeruli available by immunofluorescence.
b
Electron microscopy was not performed in 10 of the cases.