Peripheral regulatory T cells and anti-inflammatory cytokines in children with juvenile idiopathic arthritis.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is a chronic, heterogenous inflammatory disease of unclear pathogenesis. JIA is hypothesized to be linked to a defective immune regulation. Anti-inflammatory cytokines belong to the best known regulatory factors. T-regulatory cells are a crucial cellular component of immune tolerance. One of their functions is synthesis of interleukin 10 (IL-10) and transforming growth factor beta1 (TGF-β1). The aim of this study was to determine the proportion of T-regulatory cells (CD4+ CD25high FOXP3+ ) in peripheral blood, and serum levels of TGF-β1 and IL-10 in patients with JIA.

METHODS: The study included 25 patients with newly diagnosed JIA: oligoarthritis (n=17) and polyarthritis (n=8). The control group was comprised of 17 healthy children. CD4+ CD25high FOXP3+ T cells in peripheral blood were quantified by means of three-color flow cytometry. Serum concentrations of TGF-β1 and IL-10 were estimated with ELISA.

RESULTS: The proportion of peripheral CD4+ CD25high FOXP3+ cells in patients with JIA was significantly higher than in the controls (p=0.04). The two groups did not differ significantly in terms of their TGF-β1 and IL-10 concentrations.

CONCLUSIONS: At the time of diagnosis, children with JIA presented with an elevated proportion of T-regulatory cells (CD4+ CD25high FOXP3+ ) in peripheral blood. Anti-inflammatory cytokines, IL-10 and TGF-β1, are not upregulated in the serum of patients with JIA, and therefore should not be considered as biomarkers of this condition.