[The decreased proportion of CD4+CD25+FOXP3+ regulatory T cells in peripheral blood of children with juvenile idiopathic arthritis and its negative correlation with cytokine level].

Objective To investigate the expression of CD4+CD25+FOXP3+regulatory T cells(Tregs), IL-6 and TNF-α in patients with juvenile idiopathic arthritis (JIA) and its clinical significance. Methods The percentages of CD4+CD25+FOXP3+ Tregs in 58 children with JIA and 40 healthy controls were detected by flow cytometry. Serum levels of IL-6 and TNF-α in each patient was detected by chemiluminescence. The correlations between the expression of CD4+CD25+FOXP3+ Tregs and IL-6, TNF-α were analyzed by pearson correlation analysis. We measured the expression level of CD4+CD25+FOXP3+regulatory T cells, IL-6 and TNF-α of 18 cases six weeks after the treatment of tocilizumab (TCZ) in order to figure out the dynamic changes using methods above. Results The percentages of CD4+CD25+FOXP3+Tregs in juvenile idiopathic arthritis were significantly lower than those in 40 healthy volunteers, while levels of IL-6 and TNF-α were significantly higher. However, no obvious difference in the levels of CD4+CD25+FOXP3+Tregs, IL-6 or TNF-α was observed between patients with systemic and poly-articular JIA. Pearson correlation analysis showed that the percentages of CD4+CD25+FOXP3+Tregs negatively correlated with the levels of IL-6 and TNF-α, while levels of IL-6 positively correlated with the levels of TNF-α. Compared with pre-treatment of TCZ, levels of CD4+CD25+FOXP3+Tregs in post-treatment markedly increased, which however were still lower than control group while the levels of IL-6 significantly decreased, yet remained higher than control group. There was no statistical difference between post and pre-treatment in the levels of TNF-α. Conclusion The percentages of CD4+CD25+FOXP3+ Tregs in peripheral blood of JIA children decreases, and it has a negative correlation with IL-6 and TNF-α. Furthermore, the levels of CD4+CD25+FOXP3+ Tregs and IL-6 are partially restored after treatment with TCZ, which may be helpful to assess the activity of systemic JIA and the efficacy of therapy.