Up-regulation of Th17 and related cytokines in Behçet's disease corresponding to disease activity.

OBJECTIVES

The IL-23/IL-17 pathway is implicated in the development of certain inflammatory diseases. The aim of the present study was to investigate the expression of Th17 and related cytokines according to clinical activity in Behçet's disease (BD).

METHODS

Peripheral blood mononuclear cells (PBMCs) from eleven patients with active BD, eleven patients with inactive BD, ten patients with recurrent aphthous ulcers, and ten healthy controls were cultured and stained with the appropriate fluorescent antibodies for analysis by flow cytometry. ELISA assays were utilized to determine the concentrations of IL-17, IFN-γ, IL-23, and IL-12/23p40 in serum and culture supernatants. IL-12p35, IL-12/23p40, and IL-23p19 transcript levels in PBMCs were measured by real-time PCR.

RESULTS

Significantly higher frequencies of IL-17 and IFN-γ expressing CD4(+) T cells were observed in patients with active BD compared with control groups. Similarly, levels of IL-17, IL-23, IL-12/23p40, and IFN-γ in serum and supernatants were significantly elevated in patients with BD despite the fact that IL-12p35 and IL-12/23p40 mRNA expression in PBMCs was up-regulated in the inactive BD group. In the same patient, the frequency of IL-17 expressing cells decreased when the BD disease activity was stabilised.

CONCLUSIONS

The results of this study suggest that up-regulated IL-17 expression may be associated with clinical activity of BD.