TNF and polyarticular juvenile idiopathic arthritis: Consensus treatment plans developed by the Childhood Arthritis and Rheumatology Research Association (CARRA) recognize RF (and ACPA, discussed below) as poor prognostic risk factors among patients with polyarticular JIA, leading most pediatric rheumatologists to use more aggressive, early therapy (e.g., TNF inhibitors) for these patients than for patients without RF (56).