Adenosine Deaminase Isoenzymes in the Diagnosis and Monitoring of Rheumatoid Arthritis

The aim of this study was determination of the catalytic activities of adenosine deaminase (ADA), ADA1 and ADA2 isoenzymes in the serum of patients suffering from rheumatoid arthritis (RA) who were and were not treated with methotrexate (MTX), and identification of the possibilities of using these biochemical parameters in diagnosing and monitoring the treatment effects in RA. Catalytic activities of total ADA (tADA) and ADA2 in serum were determined by a spectrophotometric method. A statistically significant correlation was found between the total ADA and ADA1 values, as well as between tADA and ADA2 in the serum of all patients suffering from RA. Determination of ADA1 and ADA2 isoenzyme catalytic activities in the serum of patients who might be suffering from RA improves the diagnostic value of total ADA catalytic activity determination. ADA2 catalytic activity in serum can be a useful biochemical marker in diagnosing and monitoring RA. Decrease in ADA1 isoenzyme catalytic activities in the serum of patients suffering from RA who were treated with MTX can help in the observation of MTX therapy effects.