Comparison of Adenosine Deaminase Level in Serum and Synovial Fluid in Patients with Juvenile Idiopathic Arthritis and Its Relation to Inflammatory Acute Phase Reactants

In JIA, cell-mediated immune response results in secretion of different inflammatory products from activated lymphocytes, macrophages, fibroblasts and leukocytes in synovial joints. Adenosine deaminase (ADA) regulates this immune system activity by metabolizing adenosine through purine metabolic pathway.
The aim of this study was to compare the level of serum ADA with synovial fluid ADA in JIA patients and to see whether it can be utilized as a marker for the activity of the disease
JIA was diagnosed based on International League of Associations for Rheumatology diagnosis criteria. ADA was measured using special kits.
80% of the patients had oligoarticular and 20% polarticulare JIA. There was a significant relation between erythrocyte sedimentation rate (ESR) and high level of synovial fluid ADA. Synovial ADA level was significantly higher than serum ADA in polyarticular JIA. C-reactive protein (CRP), leukocytes and platelets count were increased in high levels of synovial fluid ADA. No correlation was observed between level of serum and synovial fluid ADA.
Synovial fluid ADA seems a more precise index than serum ADA to assess the inflammatory condition. In addition, acute-phase response reactants such as ESR, CRP, and platelets count could be suitable predicting parameters for arthritis.