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Immunoreactive granulocyte elastase in rheumatoid synovial fluid and membrane
Scandinavian Journal of Plastic and Reconstructive Surgery
|January 1, 1982
Summary
Rheumatoid arthritis synovial fluid contains high levels of granulocyte elastase, an enzyme released in active form and taken up by cells. This finding offers insights into joint inflammation mechanisms.
Area of Science:
- Biochemistry
- Immunology
- Rheumatology
Background:
- Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting joints.
- Granulocyte elastase is an enzyme implicated in inflammatory processes.
- Understanding enzyme activity in synovial fluid is crucial for RA pathogenesis.
Purpose of the Study:
- To quantify granulocyte elastase levels in rheumatoid synovial fluid.
- To investigate the form and cellular uptake of granulocyte elastase in RA joints.
- To correlate elastase levels with other inflammatory markers.
Main Methods:
- Radioimmunoassay (RIA) for granulocyte elastase quantification in synovial fluid and serum.
- Immunohistochemical staining to detect enzyme-cell interactions.
- Comparison of RA patients with controls and non-inflammatory conditions.
Main Results:
- Elevated granulocyte elastase concentrations (approx. 340 µg/l) found in rheumatoid synovial fluid compared to serum.
- No correlation between elastase levels and white blood cell counts in synovial fluid.
- Immunoreactive elastase detected bound to alpha 1-antitrypsin, indicating active release.
- Uptake of elastase-macrophage complexes observed in synovial membrane tissue.
- Equivalent serum elastase levels in RA patients on NSAIDs and controls.
Conclusions:
- Granulocyte elastase is actively released and present in rheumatoid synovial fluid.
- Macrophage-like cells actively internalize elastase-containing complexes in the synovium.
- Synovial fluid elastase concentrations may not fully represent the enzyme's activity at target sites.