Persistent improper upregulation of Th17 and TReg cells in patients with juvenile idiopathic arthritis.

Objectives Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic disease. A break in the balance between Th17 and T Reg cells has been reported as an important factor in the development of autoimmune diseases. This study aimed to analyze peripheral Th17 and T Reg cell levels in patients with JIA. Methods The balance of Th17 and T Reg cells among active and inactive JIA patients and normal control subjects were compared. Human peripheral blood mononuclear cells were isolated from the patients and controls. Surface and intracellular staining for CD4, CD25, Foxp3, IL-17, Th17, and T Reg were analyzed. Results Twenty-eight JIA patients, including 12 with active JIA and 16 with inactive JIA, and 20 health controls were analyzed. Patients with active JIA had higher Th17 (1.85 ± 1.15 vs. 1.05 ± 0.72, p = 0.008) and T Reg cells (1.1 ± 0.8 vs. 0.6 ± 0.7, p = 0.04) levels than those with inactive JIA. Among active JIA patients, remission days were highly correlated with the CD4 + IL17A + T cell percentage, 276.5 ± 137.40 days (range, 130 ∼ 525 days), p Reg percentage between JIA patients and controls in the peripheral blood. Conclusions Th17 and T Reg cell levels are elevated in patients with active JIA and there is no Th17/T Reg imbalance. The higher Th17 level predicted longer period to reach disease inactive stage. Improper Th17 up-regulation might contribute to JIA activation.