IFN-α induces IL-10 production and tilt the balance between Th1 and Th17 in Behçet disease.

Objective: Interferon alpha (IFN-α) is an effective treatment for patients with active Behçet disease (BD). Besides its antiviral property, IFN-α is a cytokine with pleiotropic effects that can generate an anti-inflammatory environment or inhibit specific inflammatory T cells such as Th1 and Th17 cells. However, it is not known, in BD patients, whether IFN-α inhibits pro inflammatory T cells, or induces anti-inflammatory properties in T cells.

Methods: Total memory CD45RO(+) T cells purified from peripheral blood mononuclear cells (PBMCs) obtained from patients with active BD (N=5), systemic lupus erythematosus (SLE, N=5) or healthy control (HC, N=6) were cultured in vitro with or without IFN-α. Levels of IFN-γ, IL-17, IL-10, IL-6, and TNF-α in the supernatants were analyzed by ELISA, Cytometric Beads Array (CBA) or intracellular cytokine staining. We analyzed the production of IL-10 on the memory subsets Th1 (mTh1), Th2 (mTh2) and Th17 (mTh17).

Results: IFN-α significantly increased IFN-γ level in memory CD4(+) T cells in BD patients and HC, but not SLE patients. IL17 was not inhibited by IFN-α in BD or in SLE patients. However, IFN-α modulated the pro- and anti-inflammatory cytokines secreted by T cells as it increased the IL-10/IL-6 ratio in BD and HC, but not SLE patients. We further demonstrated that IFN-α increased IL-10 secretion in each memory subset mTh1, mTh2 and mTh17.

Conclusions: In BD, IFN-α promotes a regulatory Th1 response through IL-10 secretion. This effect may explain the efficacy of IFN-α in inflammatory disease.