Additionally, T helper type 1 (Th1)/Th17 cytokine polarization of CD4+ T cells is a consistent finding in disease lesions and in peripheral blood where increased interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α, interleukin (IL)‐8 and IL‐17 levels have been correlated with BD activity 10. This evidence concerns the gene CD4 and Behcet disease.