Table 1.
Clinical characteristics of patients with anti-GBM disease according to circulating IgA anti-α3(IV)NC1 antibodies status
| Characteristics | Total patients (n = 107) | IgA Anti-α3(IV)NC1 antibodies Positive (n = 20) | IgA Anti-α3(IV)NC1 antibodies Negative (n = 87) | P-value |
|---|---|---|---|---|
| Demography | ||||
| Gender (male/female) | 51/56 | 11/9 | 40/47 | 0.466 |
| Age (years) | 54.4 ± 17.0 | 55.5 ± 17.7 | 54.2 ± 16.9 | 0.767 |
| Clinical features | ||||
| Smoking | 35 (32.7%) | 7 (35.0%) | 28 (32.2%) | 0.809 |
| Prodromal infection | 49 (45.8%) | 10 (50.0%) | 39 (44.8%) | 0.675 |
| Hemoptysis | 26 (24.3%) | 6 (30.0%) | 20 (23.0%) | 0.566 |
| AKD and AKI | 104 (97.2%) | 20 (100.0%) | 84 (96.6%) | 1.000 |
| SCr on diagnosis (μmol/l) | 659.6 (412.0, 932.0) | 697.3 (439.0, 975.2) | 650 (364, 932) | 0.832 |
| Oliguria/anuria | 53 (49.5%) | 13(65.0%) | 40 (46.0%) | 0.125 |
| Gross hematuria | 46 (43.0%) | 9(45.0%) | 37 (42.5%) | 0.840 |
| Microscopic hematuria | 56 (52.3%) | 11(55.0%) | 45 (51.7%) | 0.791 |
| Proteinuria | 101 (94.4%) | 19(95.0%) | 82 (94.3%) | 1.000 |
| Nephrotic syndrome | 14 (13.1%) | 1(5.0%) | 13 (14.9%) | 0.460 |
| Serum albumin (g/l) | 30.4 ± 5.4 | 29.0 ± 6.5 | 30.7 ± 5.2 | 0.231 |
| Anemia | 98 (91.6%) | 16 (80.0%) | 82 (94.3%) | 0.061 |
| Hemoglobin (g/l) | 91.5 ± 21.7 | 95.2 ± 28.2 | 90.7 ± 20.0 | 0.507 |
| ANCA | 27 (25.2%) | 6 (30.0%) | 21 (24.1%) | 0.586 |
| MPO-ANCA/PR3-ANCA/both | 26/1/0 | 6/0/0 | 20/1/0 | 1.000 |
| Anti GBM antibodies (ELISA) | 107 (100.0%) | 20 (100.0%) | 87 (100.0%) | - |
| Anti-GBM antibodies (U/ml) | 184 (105.5, 200) | 200 (183.3, 200) | 161 (85.5, 200) | 0.005a |
| Combined GN | ||||
| IgAN and HSPGN | 12 (11.2%) | 2 (10.0%) | 10 (11.5%) | 1.000 |
| MN | 12 (11.2%) | 2 (10.0%) | 10 (11.5%) | 1.000 |
| AAV | 27 (25.2%) | 6 (30.0%) | 21 (24.1%) | 0.586 |
| Other GN | 1 (0.9%) | 0 | 1 (1.1%) | 1.000 |
| Time between onset and diagnosis (median, mo) | 1.0 (0.7, 2.0) | 0.7 (0.5, 2.0) | 1.0 (0.8, 2.0) | 0.271 |
| Treatment | ||||
| Dialysis on diagnosis | 72 (67.3%) | 13 (65.0%) | 59 (67.8%) | 0.809 |
| Plasmapheresis | 106 (99.1%) | 20 (100.0%) | 86 (98.9%) | 1.000 |
| Corticosteroids | 105 (98.1%) | 20 (100.0%) | 85 (97.7%) | 1.000 |
| Corticosteroid pulses | 94 (87.9%) | 19 (95.0%) | 75 (86.2%) | 0.460 |
| Cyclophosphamide | 81 (75.7%) | 16 (80.0%) | 65 (74.7%) | 0.776 |
| Rituximab | 7 (6.5%) | 2 (10.0%) | 5 (5.7%) | 0.613 |
| Other immunosuppressive agent | 3 (2.8%) | 0 | 3(3.4%) | 1.000 |
| Outcome | ||||
| Follow-up duration (median, mo) | 30.8 (12.0, 59.0) | 27.8 (16.3, 59.8) | 32.2 (9.3, 58.4) | 0.857 |
| ESKD | 59 (55.1%) | 7 (35.0%) | 52 (59.8%) | 0.045a |
| Death | 18 (16.8%) | 6 (30.0%) | 12 (13.8%) | 0.100 |
AAV, ANCA-associated vasculitis; AKD, acute kidney disease; AKI, acute kidney injury; ANCA, antineutrophil cytoplasmic antibodies; CKD, chronic kidney disease; ESKD, end stage kidney disease; GBM, glomerular basement membrane; GN, glomerulonephritis; HSPGN, Henoch–Schönlein purpura glomerulonephritis; IgAN, IgA nephropathy; MN, membranous nephropathy; MPO, myeloperoxidase; PR3, proteinase 3; SCr, serum creatinine.
Unless otherwise indicated, values are given as mean ± SD, frequency (percentage), or median (interquartile range). P-values is the comparison between IgA Anti-α3(IV)NC1 antibodies positive and negative group.
Significant P-values.