Characteristics of 794 subjects and single marker assay results
| SLE | RA | SS | Scl | PM/DM | Others | NHV | |
|---|---|---|---|---|---|---|---|
| Age (years) | 41±1 | 59±1 | 54±2 | 51±2 | 56±2 | 53±3 | 41±1 |
| Gender (% female) | 91 | 85 | 91 | 80 | 81 | 83 | 65 |
| Ethnicity Caucasians (%) | 41 | 61 | 73 | 74 | 63 | 48 | 56 |
| African–Americans (%) | 30 | 15 | 18 | 14 | 26 | 10 | 35 |
| Asians (%) | 8 | 4 | 0 | 0 | 0 | 10 | 2 |
| Hispanics (%) | 20 | 19 | 9 | 9 | 11 | 31 | 6 |
| Other (%) | 2 | 2 | 0 | 3 | 0 | 0 | 1 |
| Duration of disease (years) | 11±1 | 12±1 | 10±3 | 8±1 | 3±1 | 6±1 | NA |
| ANA ≥20 units (%) | 89 | 32 | 89 | 66 | 74 | 31 | 10 |
| dsDNA >301 units (%) | 33 | 4 | 0 | 6 | 0 | 7 | 0 |
| Anti-Sm >10 units (%) | 14 | 0 | 0 | 0 | 0 | 0 | 0 |
| Anti-MCV >70 units (%) | 3 | 47 | 9 | 6 | 4 | 3 | 0 |
| Jo1 >10 units (%) | 0 | 0 | 0 | 0 | 15 | 0 | 0 |
| Scl-70 >10 units (%) | 0 | 0 | 3 | 20 | 0 | 0 | 0 |
| SS-A/Ro >10 units (%) | 39 | 10 | 79 | 11 | 26 | 3 | 1 |
| SS-B/La >10 units (%) | 9 | 1 | 39 | 3 | 0 | 0 | 0 |
| CENP >10 units (%) | 2 | 3 | 3 | 17 | 0 | 0 | 1 |
| Reduced C3 (%) | 33 | 4 | 6 | 12 | 0 | 0 | 6 |
| Reduced C4 (%) | 32 | 7 | 3 | 0 | 4 | 4 | 4 |
| Reduced C3 or C4 (%) | 45 | 10 | 9 | 12 | 4 | 4 | 8 |
| U1 RNP >10 units (%) | 27 | 0 | 3 | 6 | 0 | 10 | 0 |
| EC4d net MFI | 21±3 | 7±1 | 10±2 | 7±1 | 8±1 | 8±1 | 5±1 |
| >14 units (%) | 46 | 5 | 12 | 11 | 10 | 1 | |
| >75 units (%) | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| BC4d net MFI | 106±6 | 32±2 | 26±4 | 32±5 | 27±4 | 46±19 | 23±1 |
| >60 units (%) | 53 | 9 | 9 | 6 | 4 | 10 | 1 |
| >200 units (%) | 14 | 0 | 0 | 0 | 0 | 3 | 0 |
| Antibody specificity comp. (%) | 12 | 48 | 52 | 46 | 15 | 3 | 1 |
Age, EC4d, BC4d and disease duration are expressed as average±SEM. The group of subjects with other rheumatic diseases included granulomatosis with polyangiitis (5 patients), fibromyalgia (13 patients), vasculitis (10 patients) and antiphospholipid syndrome (1 patient)). The antibody specificity component corresponds to positivity to either anti-MCV (>70 units), SS-B/La (>10 units), Jo-1 (>10 units), Scl-70 (>10 units) or CENP (>10 units), and was used to calculate the index score (tier 2).
ANA, antinuclear antibodies; anti-Sm, anti-Smith; dsDNA, double-stranded DNA; MFI, mean fluorescence intensity; NA, not applicable; NHV, normal healthy volunteers; PM/DM, polymyositis/dermatomyositis; RA, rheumatoid arthritis; Scl, scleroderma; SLE, systemic lupus erythematosus; SS, Sjogren's syndrome; anti-MCV, anti-mutated citrullinated vimentin; EC4d, complement C4d levels on erythrocytes; BC4d, complement C4d levels on cells; CENP, Centromere extractable nuclear antigen.