ADA and adult-onset Still disease: We analyzed the difference in serum ADA activity between patients with abnormal transaminase and normal transaminase, and found that AOSD patients with normal transaminase had significantly lower ADA activity than patients with abnormal transaminase (25.10 ± 2.91 vs 50.06 ± 4.86, p = 0.003) but significantly higher than healthy controls (25.10 ± 2.91 vs 10.79 ± 0.46, p < 0.0001) (Fig. 2c).