TNF and Behcet disease: In view of the fact that IFN-γ, TNF-α, and IL-17 can be secreted by PBMCs stimulated with S-Ag peptides, we analyzed the relationships between IFN-γ and TNF-α or IL-17 upon S-Ag stimulation in healthy controls, active BD patients with a response to S-Ag, active BD patients without a response to S-Ag, and inactive BD patients were analyzed, respectively.