Potential role of adenosine deaminase in the diagnosis of adult-onset Still's disease.

Adult-onset Still's disease (AOSD) is a systemic inflammatory autoimmune disorder of unknown etiology and pathogenesis. There are no specific laboratory tests for AOSD. To investigate the potential role of adenosine deaminase (ADA) in the diagnosis of AOSD and analyze the correlation among ADA, LDH and WBC (white blood cell count), the serum levels of ADA and LDH in 26 patients with active untreated AOSD, 40 patients with active systemic lupus erythematosus (SLE) as disease control and 48 healthy volunteers as healthy control were determined using automatic biochemical analyzer (Olympus AU2700, Japan). WBC was examined by automatic blood cell analyzer (Beckman Coulter Hmx, America). Significantly higher levels of serum ADA, LDH and WBC were found in active untreated AOSD patients than in active SLE patients and healthy volunteers (F = 27.823; P = 0.000; F = 28.458, P = 0.000; F = 51.929, P = 0.000). Serum ADA were related to LDH level in patients with AOSD patients (r = 0.786, P = 0.000 < 0.01). Both ADA and LDH were not related to WBC (r = 0.244, P = 0.229 > 0.01; r = 0.054, P = 0.794 > 0.01). This is the first study to show that serum ADA could play an important role in AOSD and may be an important biomarker for the diagnosis of AOSD. Serum ADA could be another diagnostic marker independent from whole blood WBC.