We assayed aqueous humor (AH) samples from patients with Behçet's disease (BD), Vogt-Koyanagi-Harada (VKH) disease, and HLA-B27-associated uveitis and control patients for the proinflammatory cytokines IL-15, IL-17, interferon-γ and tumor necrosis factor-α and the immunosuppressive cytokine IL-10. Cytokine levels were significantly higher in the three disease groups than in controls. In patients with similar disease activity, levels of IL-15 and IFN-γ were significantly higher in BD patients than in VKH and HLA-B27-associated uveitis groups. Logistic regression identified a significant negative correlation between BD and high levels of IL-10 and a significant positive correlation between VKH disease and high levels of IL-10. The proinflammatory cytokines versus IL-10 ratios were significantly higher in BD compared with other groups. These data suggest that both T helper (Th) 1 and Th17 cells are involved in endogenous uveitis immunopathogenesis. BD is characterized by extensive Th1 polarization, severe proinflammatory conditions and a low immunosuppressive status.