Interleukin-1 Receptor Antagonist (IL-1RA) (ANAKINRA) IN SEVERE SYSTEMIC-ONSET JUVENILE IDIOPATHIC ARTHRITIS

Inclusion Criteria: * SO-JIA (Edmonton's revision of Durban's consensus conference criteria) * Age: at least 2 years and less than 20 years at treatment initiation * Disease duration of at least 6 months * Failure of corticosteroid treatment or requirement for corticosteroid treatment at a daily dose equal to or over 0.3 mg/kg (10 mg in patients whose weight is over 34 kg) * Active and severe systemic symptoms and/or arthritis as assessed by an experienced pediatric Rheumatologists, with at least 3 of the following criteria when assessing Giannini's core-set items: 1) physician global assessment of disease activity of at least 20/100; 2) parent/patient assessment of disease effect on overall well-being of at least 20/100; 3) functional disability with a Children Health Assessment Questionnaire (CHAQ, Ref \[9\]) score equal to or higher than 0.375/3; 4) 2 joints or more with active arthritis 5) 2 joints or more with non-irreversible limited range of motion (irreversible limited range of motion will be defined by radiological evidence of irreversible joint damage and ankylosis) 6) erythrocyte sedimentation rate (ESR) equal to or higher than 20. * In the absence of disease-related fever, either CRP or first hour ESR or both have to be over the upper limit of normal values so that treatment effect on the systemic part of the disease can be objectively evaluated. * Patients with polyarthritis (at least 5 joints with inflammation and/or limitation of motion) will be eligible for t…