Amino Acid Naphthylamidases in the Synovial Fluid of Patients with Rheumatoid Arthritis: The Effect of Intra-articular Corticosteroid Treatment

Abstract

Naphthylamidase levels were found to be elevated in the synovial fluids in a group of patients with rheumatoid arthritis but also in osteoarthritis with synovitis, when compared with non-inflammatory effusions. In the individual case the enzyme levels could not assist in differentiating between different diseases. One isozyme was found in all synovial fluids. Additionally, one isozyme of lysosomal provenance was found in inflammatory effusions irrespective of enzyme levels, diagnosis, or corticosteroid treatment Intra-articular application of hydrocortisone reduced the enzyme activity significantly in treated joints while the contralateral untreated joints remained unaltered.