IL-22-secreting Th22 and IFN-γ-secreting Th17 cells in Behçet's disease

Abstract

Objective: Behçet's disease (BD) is a systemic inflammatory disease with unknown etiology. Studies have shown that some T helper (Th) 1-associated cytokines have role in the inflammation of BD. The CD4(+) Th cells can be differentiated into Th1, Th2, Th17 and Th22 secrete different cytokines to regulate immune system. In this study, cytokine secretion of Th subsets in BD was investigated.

Methods: The study group consisted of 26 BD patients with mucocutaneous involvement and 12 healthy subjects. Lymphocyte subpopulations, IL-5, IL-10, IL-17, IL-22 and IFN-γ secretion of CD4(+) T and Foxp3(+) Treg cells were determined by flow cytometry.

Results: Compared with healthy subjects, Th1 (IL-17A(-)IL-22(-)IFN-γ(+)), Th22 (IL-17A(-)IL-22(+)IFN-γ) and IL-17A(+)IFN-γ(+)-secreting cells were significantly increased, and the percentage of Treg cells were dramatically reduced in BD patients. The frequency of recurrent oral ulcers was associated with increased Th22 cells.

Conclusions: Our study describes an association between Th22 cell subset and IL-17A(+) IFNγ(+)-secreting cells with mucocutaneous BD. These findings revealed that reduced levels of Tregs and increased levels of Th1 and Th22 cells as well as Th17/Th1 cells might be associated with the pathogenesis of BD.

Keywords: Behçet's disease; Cytokines; IL-22; Th17 cells; Th22 cells.