Table 1.
Clinical and pathologic characteristics at presentation
| Characteristic | Value (N=46) |
|---|---|
| Age, yr | 52±13 |
| Male, n (%) | 25 (54) |
| 24-h urine protein, g/24 h | 5.3 (2.3–10.3) |
| Serum albumin, g/dl | 2.7±0.6 |
| Hematuria, n (%) | 41 (89) |
| Urine red blood cells, per µl | 61 (25–153) |
| Serum creatinine at biopsy, mg/dl | 1.7 (1.3–3.8) |
| eGFR at biopsy, ml/min per 1.73 m2 | 37 (16–62) |
| Low C3a, n (%) | 14/45 (31) |
| Low C4b, n (%) | 8/45 (18) |
| Hematologic studies, n (%) | |
| Serum or urine clone detection | 5/45 (11) |
| Positive serum immunofixation | 5/45 (11) |
| Positive urine immunofixation | 1/45 (2) |
| Positive serum protein electrophoresis | 2/19 (11) |
| Positive urine protein electrophoresis | 0/14 (0) |
| Abnormal serum free light chain ratioc | 0/37 (0) |
| Clone detection of bone marrow | 8/36 (22) |
| Positive serum cryoglobulin | 20/38 (53) |
| IF | |
| IgG1 κ/IgG3 κ/IgG3 λ/IgM λ | 5/31/9/1 |
| Deposition of C3, n (%) | 46 (100) |
| Deposition of C1q, n (%) | 38 (83) |
| Light microscopy | |
| No. of glomeruli | 30 (23–42) |
| % of globally sclerotic glomeruli | 6 (0–11) |
| Predominant histologic pattern | |
| Membranoproliferative glomerulonephritis, n (%) | 36 (78) |
| Mesangial proliferative glomerulonephritis, n (%) | 6 (13) |
| Endocapillary proliferative glomerulonephritis, n (%) | 3 (7) |
| Atypical membranous nephropathy, n (%) | 1 (2) |
| Crescents, n (%) | 18 (39) |
| Diffused, n (%) | 1 (2) |
| Electron microscopic, n (%) | |
| Location of granular electron-dense deposits | |
| Mesangial | 42/45 (93) |
| Subendothelial | 38/45 (84) |
| Subepithelial | 20/45 (44) |
| Intramembranous | 11/45 (24) |
IF, immunofluorescence.
a
The normal range of C3 is 60–150 mg/dl.
b
The normal range of C4 is 12–36 mg/dl.
c
The normal serum free light chain ratio is 0.26–1.65 for patients with eGFR ≥60 ml/min per 1.73 m2 and 0.37–3.10 for patients with eGFR >60 ml/min per 1.73 m2.
d
Diffuse, ≥50% of glomeruli.