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

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.

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.

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.

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.