Takayasu arteritis (TA) is an autoimmune arteritis of unknown etiology. Currently, the erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) levels are widely used to monitor disease activity of TA. However, sometimes it is difficult to reflect inflammatory symptoms in either CRP or ESR values, especially in TA patients with immunosuppressive therapies. Therefore, higher-accuracy biomarkers for evaluating disease activity need to be explored.
We examined 21 Japanese patients diagnosed with TA; 17 TA patients were treated with prednisone with or without additional immunosuppressive therapies and the remaining 4 patients were treated with infliximab, a human monoclonal anti-tumor necrosis factor (TNF)-α antibody. In active phase, the serum levels of both TNF-α and interleukin (IL)-6 were significantly higher than in healthy subjects, as is the case with both the levels of CRP and ESR. In contrast, the levels of both IL-12 and IL-23 remained in the normal range. Both TNF-α and IL-6 levels were markedly decreased in response to therapies, on equality with both CRP and ESR levels. Regarding the TA patients treated with infliximab, both CRP and IL-6 levels tended to be decreased after infliximab therapy. Conversely, TNF-α level after infliximab therapy was higher than before therapy.
Both TNF-α and IL-6 levels, but not IL-12 or IL-23 levels, in the serum could be potent biomarkers that can reflect the activity of TA.