PDCD1 and juvenile idiopathic arthritis: Patients with JIA had a significantly higher PB PD1 expression on both CD4 and CD8 T-cells compared to HCs (CD4: 1.24% Q1–Q3: 0.54–2.9 vs 0.32% Q1–Q3: 0.17–1, p=0.007, CD8: 1.6% Q1–Q3: 0.81–3.8 vs 0.4% Q1–Q3: 0.26–1.04, p=0.002, Figures 1 and 2).