Increased serum adenosine deaminase activity in patients with adult-onset Still's disease

Background Adult-onset Still's disease (AOSD) is a systemic inflammatory disease of unknown etiology, lacking specific diagnosis and disease activity evaluation indicators. This study will analyze the activity and clinical significance of Adenosine deaminase (ADA) in AOSD patients. Methods Totally 53 AOSD patients, 60 patients with other autoimmune diseases including systemic lupus erythematosus (SLE), sjogren syndrome (SS) and rheumatoid arthritis (RA), as well as 60 healthy subjects were included in this study. AOSD activity was determined by Pouchot score. We analyzed the correlation between ADA activity and clinical parameters. In addition, the correlation between ADA activity and disease activity score was also analyzed. Results This study showed that the activity of ADA in AOSD patients was significantly higher than that of healthy controls, SLE, SS and RA patient groups ( p < 0.0001). The ADA activity of AOSD patients decreased significantly after systemic treatment ( p < 0.0001). Correlation analysis showed that ADA activity was positively correlated with ALT( r = 0.54, p < 0.0001), AST ( r = 0.82, p < 0.0001) and serum ferritin ( r = 0.67, p < 0.001). ADA activity was negatively correlated with white blood cell ( r = − 0.42, p = 0.002) and platelet counts ( r = − 0.44, p = 0.001). We also found a significant positive correlation between the activity of ADA and Pouchot score in AOSD patients ( r = 0.51, p = 0.001). Receiver operating characteristic (ROC) curve analysis showed that ADA activity had a sensitivity of 93.3%, and a specificity of 83% for the diagnosis of AOSD, with an area under the curve of 0.93. Conclusion This study showed that serum ADA activity can be used as a potential biomarker for AOSD diagnosis and disease activity assessment.