Background
Behcet's disease (BD) is an autoinflammatory disease with a unique distribution characterized by uveitis, and mucosal and skin lesions, which are characterized by the prominent infiltration of immune cells such as lymphocytes and neutrophils. A novel helper T-cell subset Th17, IL-17-producing helper T cells, has been appreciated [1]. IL-17 is involved in the induction of a series of chemokines, growth factors, proteases, and cytokines, and production of IL-17 results in induction of neutrophil migration and chronic inflammation [2]. Based on these findings, we hypothesized that Th17 is involved in the pathogenesis of BD.