Adult onset Still's disease (AOSD) is a systemic inflammatory disorder characterized by fever, arthritis, and rash. Although the pathogenesis is not known, immunologically mediated inflammation occurs in active AOSD. To evaluate the pathogenesis and disease activity of AOSD, we measured serial serum concentrations of several cytokines in patients with active and inactive disease.
Seventeen patients diagnosed as having AOSD were enrolled. We analyzed clinical and laboratory findings retrospectively. Serial serum samples were obtained from 14 patients with active and inactive AOSD. Interleukin 18 (IL-18), soluble IL-2 receptor (sIL-2R), IL-6, interferon-g (IFN-g), and IL-8 were determined by ELISA.
Serum levels of IL-18, IFN-g, and IL-8 were significantly higher in patients with AOSD than in healthy controls (p < 0.01), but there were no significant differences between patients with active and inactive AOSD. Serum sIL-2R levels tended to be higher in the active state than in healthy controls, but there was no statistically significant difference between the 2 groups. Serum sIL-2R levels decreased significantly with antiinflammatory therapy (p < 0.05). Serum IL-18 and sIL-2R levels correlated significantly with serum ferritin levels in the active AOSD group (p < 0.05).
Overproduction of IL-18 may contribute to the pathogenic mechanism of AOSD, and serum sIL-2R levels may be used as a marker for monitoring disease activity in AOSD.