Table 1 Prevalence of autoantibodies during the first year of disease in 192 patients from the Nordic juvenile idiopathic arthritis database classified after a median of eight years of disease according to the ILAR* criteria
ILAR* category | Total cohort n (%) | Girls/boys n (% girls) | IgM RF- positive n (%) | IgA RF-positive n (%) | IgG anti-CCP positive n (%) | IgG anti-collagen II positive n (%) |
|---|---|---|---|---|---|---|
Systemic | 9 (4.7%) | 5/4 (55%) | 1 | 0 | 1 | 0 |
Oligoarticular persistent | 90 (46.9%) | 60/30 (66.6%) | 2 | - | - | 2 |
Oligoarticular extended | 8 (4.2%) | 8/0 (100%) | 1 | 1 | 1 | - |
Polyarticular RF-negative | 40 (20.8%) | 30/10 (75.0%) | - | 1 | 1 | 2 |
Polyarticular RF-positive | 1 | 1/0 | 1 | 1 | - | - |
Juvenile psoriatic arthritis | 1 | 0/1 | - | - | - | - |
Enthesitis-related arthritis | 15 (7.8%) | 5/10 (33.3%) | - | 2 | 1 | 1 |
Undifferentiated arthritis | 28 (14.6%) | 24/4 (85.7%) | 2 | 1 | 1 | 1 |
Total | 192 | 133/59 (69.3%) | 7 (3.6%) | 6 (3.1%) | 5 (2.6%) | 6 (3.1%) |