IL6 and Behcet disease: Elevated pro-inflammatory cytokines had been reported to be associated with greater symptom burden in BD (14, 15), and correlation between severity of affective symptoms and serum levels of IL-6, sIL-2R, sIL-6R, TNF-α and tumor necrosis factor receptor 60 and 80 kDa (sTNFR60/80) was found in several studies (16–21).