Role of IL-22-and TNF-α Producing Th22 Cells in Uveitis Patients with Behcet's Disease

Behcet's disease is a systemic inflammatory disorder with recurrent episodes of oral ulceration, skin lesions, genital ulceration, and intraocular inflammation (uveitis). The intraocular inflammation is strictly associated with Th effector cells. IL-22 is a member of the IL-10 cytokine family that is involved in inflammatory processes. Recently, Th22 cells were identified as a Th cell population that produces IL-22 and TNF-alpha and are distinct from Th1, Th2, and Th17 cells. In this study, we established Th22-type T cell clones from ocular samples taken from Behcet's disease patients with active uveitis. These clones produced large amounts of IL-22 and TNF-alpha but not the Thl cytokine IFN-gamma and the Th17 cytokine IL-17. CD4(+) T cells from the peripheral blood of Behcet's disease patients differentiated into Th22 cells in the presence of IL-6 and TNF-alpha in vitro. The polarized Th22 cell lines produced large amounts of IL-22, and the polarized Thl and Th17 cells also produced IL-22. In the presence of anti TNF-alpha- and anti IL-6-blocking Abs, Behcet's disease Th22-type T cells failed to produce IL-22. In addition, infliximab-pretreated Th22 cells and Th22-type ocular T cells produced less IL-22 and TNF-alpha. Moreover, IL-22 producing T cells were isolated from mice with experimental autoimmune uveitis, an animal model of Behcet's disease, and the intraocular T cells from uveitis models produced large amounts of IL-22 in the presence of retinal Ags. Our results suggest that inflammatory cytokines IL-22 and TNF-alpha may play a key role in the ocular immune response in Behcet's disease. The Journal of Immunology, 2013, 190: 5799-5808.