Objectives Laboratory assessment of disease activity is one of the main difficulties in patients with Takayasu's arteritis (TAK), during follow-up. To date, no biomarker is validated for clinical activity in TAK. In this study, we aimed to investigate serum GM-CSF, IL-6, IL-8, IL-10, IL-18 and IL-23 levels and their correlations with disease activity in patients with TAK.
Methods The study included 74 patients (age: 41.8±13.5 years, F/M: 64/10) with TAK fulfilling ACR criteria and 42 age and sex-matched healthy controls (age: 38.1±7.4 years, F/M: 38/4). TAK patients were evaluated by physician's global assessment (PGA; active/inactive) and by Kerr et al. definition (if available in the current visit) in terms of clinical activity. Fifty-one of 74 patients had a follow-up visit. Commercial ELISA kits were used for the measurement of serum GM-CSF, IL-6, IL-8, IL-10, IL-18 and IL-23. ESR and CRP levels were also measured.
Results At baseline, 37 (50%) patients were active according to PGA. Kerr' activity criteria were available for 62 patients and 24.2% (n=15) of these were active. Serum IL-8 and IL-18 levels were significantly higher in patients with TAK, whereas GM-CSF, IL-6, IL-10, IL-23 levels were similar to healthy controls. There was no difference between active and inactive patients regarding any cytokine level. ESR significantly correlated with IL-23 and CRP with IL-18 levels. Serum IL-6, IL-8 and IL-10 levels were significantly higher in patients taking corticosteroid therapies. In the follow-up visit, clinical activity rate decreased to 19.6% from 50% according to PGA. IL-8 levels significantly decreased and IL-23 levels significantly increased in follow-up compared to baseline.
Conclusions We found significantly increased IL-8 and IL-18 level in patients with TAK and IL-18 levels correlated with CRP. IL-8 levels significantly decreased in the follow-up together with a decrease in the rate of clinical activity. These findings suggest that IL-8 and IL-18 might be important mediators for TAK pathogenesis and their blockage might be new therapeutic approaches.
Disclosure of Interest None declared