Patient characteristics (validation cohort)
| HC | PsA | RA | SLE | |
| Number of samples | 31 | 20 | 106 | 22 |
| Per cent female | 58% | 55% | 72% | 100% |
| Age, mean | 35 | 55 | 61 | 36 |
| Age, range | (23; 76) | (32; 74) | (19; 88) | (19; 68) |
| Per cent RF positive | nd | 10% | 70% | nd |
| Per cent ACPA positive | nd | 10% | 75% | nd |
| Patients on corticosteroids | nd | 5 | 37 | 14 |
| Mean steroid dose | nd | 7.6 mg | 6.4 mg | 9.2 mg |
| Patients on DMARDs | nd | 14 | 71 | 22 |
| Methotrexate | nd | 8 | 43 | 3 |
| Leflunomide | nd | 3 | 25 | 0 |
| Sulfasalazine | nd | 4 | 3 | 0 |
| Hydroxychloroquine | nd | 0 | 1 | 17 |
| Ciclosporin | nd | 0 | 0 | 1 |
| Mycophenolate mofetil | nd | 0 | 0 | 8 |
| Azathioprine | nd | 1 | 2 | 4 |
| Patients on biologicals | nd | 7 | 24 | 6 |
| Tumour necrosis factor inhibitors | nd | 4 | 14 | 0 |
| Anti-IL-6 antibody | nd | 0 | 5 | 0 |
| Anti-IL-12/23 antibody | nd | 1 | 0 | 0 |
| Anti-IL-17A antibody | nd | 2 | 0 | 0 |
| Abatacept | nd | 0 | 4 | 0 |
| Belimumab | nd | 0 | 0 | 4 |
| Rituximab/Obinutuzumab | nd | 0 | 1 | 2 |
| Patients on JAK inhibitors | nd | 0 | 20 | 0 |
Numbers represent absolute numbers except for the the gender row; numbers in the latter represent the percentage of female patients. Of note, two female patients (aged 36 years and 66 years) were punctured twice.
DMARDs, disease-modifying antirheumatic drugs; HC, healthy control; IL, interleukin; JAK, Janus kinase ; nd, not determined; PsA, psoriatic arthritis; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus.