TFRC and juvenile idiopathic arthritis: Objectives: The main goal of this study was to characterize the frequency and phenotype of B, Tfh and Tfr cells in peripheral blood and the cytokine environment present in circulation in children with with extended oligoarticular JIA (eoJIA) and polyarticular JIA (pJIA) when compared to healthy controls, children with persistent oligoarticular JIA (poJIA) and adult JIA patients