Participant demographics and clinical characteristics
| LN | SLE | Biopsy control | HD | ||
| n=47* | n=17 | n=9 | n=19† | ||
| Demographics | n (%) | n (%) | n (%) | n (%) | |
| Age | <20 | 0 (0) | 0 (0) | 1 (11) | 1 (6) |
| 20–29 | 15 (36) | 9 (53) | 2 (22) | 7 (39) | |
| 30–39 | 12 (29) | 3 (18) | 2 (22) | 4 (22) | |
| 40–49 | 9 (21) | 1 (6) | 1 (11) | 4 (22) | |
| 50–59 | 5 (12) | 3 (18) | 0 (0) | 2 (11) | |
| 60+ | 1 (2) | 1 (6) | 3 (33) | 0 (0) | |
| Gender | Female | 35 (83) | 15 (88) | 5 (56) | 16 (89) |
| Male | 7 (17) | 2 (12) | 4 (44) | 2 (11) | |
| Race | Black | 37 (88) | 17 (100) | 3 (33) | 15 (83) |
| White | 3 (7) | 0 (0) | 6 (67) | 3 (17) | |
| Other | 2 (5) | 0 (0) | 0 (0) | 0 (0) | |
| Clinical characteristics and LN therapies | |||||
| Newly diagnosed LN‡ (%) | 52 | ||||
| SLEDAI-2K Global score, mean (SD) | 8.46 (5.15) | ||||
| Proteinuria§ (g/g) | 2.66 (2.11) | ||||
| Elevated anti-dsDNA antibodies (%) | 67 | ||||
| NIH-AI and NIH-CI indices¶ | |||||
| NIH-AI score, mean (SD) | 7.0 (4.88) | ||||
| NIH-CI score, mean (SD) | 5.2 (2.30) | ||||
| Abnormal complement concentration (%) | |||||
| C3 low | 62 | ||||
| C4 low | 48 | ||||
| Baseline treatments (%) | |||||
| Azathioprine | 5 | ||||
| Belimumab | 2 | ||||
| Cyclophosphamide | 10 | ||||
| Cyclosporine | 0 | ||||
| Dapsone | 0 | ||||
| Hydroxychloroquine | 74 | ||||
| Methotrexate | 2 | ||||
| Mycophenolate mofetil | 50 | ||||
| Prednisone | 71 | ||||
Clinical characteristics, abnormal complement concentrations and baseline treatments were not available for the SLE, biopsy control and HD control groups.
*Data available for 42 of the 47 patients with LN. Five patients with LN did not provide urine at baseline. Percentages are based on the data available for 42 patients with LN.
†Data available for 18 of the 19 HD controls. Percentages are based on the data available for 18 participants.
‡Diagnosed at first study visit following evaluation of the kidney biopsy.
§Measured as spot urine protein/spot urine creatinine.
¶Data available for 43 of the 47 patients with LN.
C3, complement 3; C4, complement 4; dsDNA, double-stranded DNA; HD, heathy donor; LN, lupus nephritis; NIH-AI, National Institutes of Health Activity Index; NIH-CI, National Institutes of Health Chronicity Index; SLEDAI-2K, SLE Disease Activity Index 2000.