CD4 and juvenile idiopathic arthritis: Treg (CD4+CD25hi or CD4+FoxP3+) have been shown to play an important role in protecting against Vogt-Koyanagi-Harada (VKH), ocular BD, JIA-associated uveitis and other NIUs by functionally suppressing Th1 and Th17 cells [66,67,78,79].