Cytokine inhibitors: soluble tumor necrosis factor receptor 1 and interleukin-1 receptor antagonist in Behçet’s disease

Serum levels of proinflammatory cytokines, interleukin-1 beta (IL-1β), tumor necrosis factor alpha, (TNF-α), and their inhibitors, IL-1 receptor antagonist (IL-1ra) and soluble TNF receptor 1 (sTNFR1), were determined by enzyme-linked immunosorbent assay in 104 patients with Behçet’s disease (65 active, 39 inactive) and 40 healthy controls. The levels of IL-1β and IL-1ra were significantly higher in both active and inactive patients than in control subjects (P<0.01 and P< 0.01, respectively). The concentrations of TNF-α and sTNFR1 were found to be higher in active patients than in controls (P< 0.01 and P< 0.001, respectively). There were no significant differences in the serum levels of these cytokines and their inhibitors between active and inactive patients. Significant increases in mean C-reactive protein level and erythrocyte sedimentation rate were found in patients with active vs inactive disease (P< 0.001 and P< 0.05, respectively). C-reactive protein values correlated with erythrocyte sedimentation rate but not with cytokines or their inhibitors. Our conclusion is that elevated serum TNF-α and sTNFR1 seem to be important inflammatory mediators in Behçet’s disease. The statistically significant increase in these levels may arise from the severity of inflammation in the tissue or organ involved.