Table 1.
Clinical characteristics of the studied population.
| Healthy controls | All SAD | RA | SLE | SSc | SjS | MCTD | APS | UCTD | |
|---|---|---|---|---|---|---|---|---|---|
| Age (years±SD) | 46.8 ± 13.2 | 52.3 ± 14.3 | 58.0 ± 12.43 | 46.1 ± 13.8 | 58.1 ± 12.9 | 58.6 ± 12.8 | 50.5 ± 14.4 | 48.1 ± 12.2 | 52.6 ± 14.6 |
| Sex (F:M) | 478:138 | 1724:255 | 294:79 | 430:33 | 335:62 | 356:23 | 84:14 | 76:30 | 149:14 |
| SAD duration (years±SD) | – | 11.9 ± 9.2 | 12.9 ± 9.9 | 14.3 ± 9.7 | 10.9 ± 9.0 | 10.7 ± 7.8 | 11.4 ± 9.7 | 10.0 ± 7.6 | 8.86 ± 7.74 |
| SAD activity (mm) | – | 22.3 ± 19.8 | 21.1 ± 20.4 | 18.9 ± 17.6 | 30.9 ± 21.2 | 24.5 ± 18.6 | 24.5 ± 18.95 | 18.1 ± 24.7 | 22.1 ± 20.75 |
| No/infection/cancer | – | 1782/44/153 | 349/4/20 | 412/26/25 | 352/3/42 | 338/7/34 | 92/1/5 | 85/2/9 | 145/2/16 |
| No/past/present kidney | – | 1148/126/705 | 241/11/121 | 217/77/169 | 266/10/121 | 202/11/166 | 70/5/23 | 54/3/49 | 98/9/56 |
| FLC-kappa (mg/L) | 16.5 ± 14.6 | 11.7 ± 4.30 | 13.85 ± 8.28 | 20.9 ± 22.3 | 17.1 ± 12.6 | 21.2 ± 18.7 | 19.9 ± 14.7 | 17.2 ± 10.7 | 13.7 ± 8.39 |
| FLC-lambda (mg/L) | 13.7 ± 8.97 | 10.8 ± 3.77 | 12.1 ± 6.61 | 16.7 ± 11.0 | 15.0 ± 10.4 | 16.0 ± 11.0 | 15.9 ± 9.14 | 14.7 ± 7.27 | 12.5 ± 6.04 |
| Total FLC (mg/L) | 31.2 ± 22.5 | 23.4 ± 7.32 | 25.85 ± 13.8 | 37.5 ± 31.2 | 32.2 ± 21.2 | 37.2 ± 27.8 | 35.7 ± 22.2 | 31.7 ± 17.1 | 26.0 ± 13.7 |
| Ratio K/L | 1.21 ± 0.51 | 1.14 ± 0.40 | 1.21 ± 0.62 | 1.22 ± 0.54 | 1.19 ± 0.45 | 1.32 ± 0.61 | 1.26 ± 0.45 | 1.17 ± 0.35 | 1.10 ± 0.34 |
| Treatment | |||||||||
| Antimalarial | – | 703/1979 | 61/373 | 325/463 | 30/397 | 139/379 | 45/98 | 26/106 | 78/163 |
| Steroids | 691/1979 | 165/373 | 239/463 | 99/397 | 80/379 | 49/98 | 8/106 | 51/163 | |
| IS | – | 675/1979 | 283/373 | 162/463 | 106/397 | 60/379 | 39/98 | 4/106 | 23/163 |
| Biologics | – | 183/1979 | 165/373 | 0/463 | 10/397 | 0/379 | 4/98 | 0/106 | 5/163 |
Abbreviations: SAD: systemic autoimmune disease; RA: rheumatoid arthritis; SLE: systemic lupus erythematosus; SSc: systemic sclerosis; SjS: Sjögren's syndrome; MCTD: mixed connective tissue disease; APS: primary antiphospholipid syndrome; UCTD: undifferentiated connective tissue disease; IS: immunosuppressant; FLC: free light chains; F:M female versus Male; SD: standard deviation.