FOXP3 and juvenile idiopathic arthritis: We have also found that children with JIA had similar frequencies of Tfh (CD4+CD25-FoxP3−CD45RO+CXCR5+) and Tfr (CD4+CD25+FoxP3+CXCR5+) cells when compared with healthy controls and no significant differences were detected in Tfr/ Tfh cells ratio (figure 3D).