Adult-onset Still's disease with macrophage activation syndrome diagnosed and treated based on cytokine profiling: a case-based review.

Adult-onset Still's disease (AOSD) is a relatively rare systemic inflammatory disorder and is diagnosed using various sets of classification criteria, with the Yamaguchi criteria as the most widely used criteria. Herein, we present the case of a 21-year-old woman admitted with a high fever, lasting for over 1 month, who did not fulfill the Yamaguchi criteria. However, by analyzing the inflammatory cytokine profile, we defined this case as AOSD based on a greatly elevated serum interleukin-18 level. In addition, we predicted the occurrence of macrophage activation syndrome by a characteristic increase in the soluble tumor necrosis factor receptor II level, which allowed a timely intervention for this malicious complication. Therefore, we suggest that cytokine profiling will be useful for the diagnosis and management of AOSD.