Objective: To investigate serum profiles of inflammatory cytokines in patients with Takayasu's arteritis (TA) and to determine their correlations with disease activity of TA.
Methods: Forty-nine patients with TA and 12 age- and sex-matched controls were studied. Blood samples were obtained and were divided into active and stable disease groups. Paired blood samples were available in 19 patients at the active stage before treatment and at the remitted stage after treatment. Serum tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-6, IL-12 and IL-18 levels were determined by enzyme-linked immunosorbent assay.
Results: Serum TNF-alpha, IL-6 and IL-18 levels of patients with TA were significantly higher than those of controls (P<0.05), but IFN-gamma and IL-12 levels were not. Serum IL-6 and IL-18 levels were significantly higher in the active disease group than in the stable disease group (P<0.05), but the levels of TNF-alpha were not different between the groups. In the 19 patients with paired samples, serum IL-18 levels at the remitted stage after treatment were significantly decreased compared with the active stage before treatment (P<0.001). The changes in IL-18 levels between active and remitted stages correlated well with changes in erythrocyte sedimentation rate (P<0.001).
Conclusion: Serum IL-18 and IL-6 levels were elevated in patients with TA, especially in those with active disease. Serum IL-18 levels correlated well with disease activity of TA. These results suggest that IL-6 and IL-18 might contribute to the pathogenesis of TA and that IL-18 could be a useful marker for monitoring disease activity of TA.