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Published on: January 7, 2019
Terminal complement pathway activation and low lysis inhibitors in rheumatoid arthritis synovial fluid
K Høgåsen1, T E Mollnes, M Harboe
1Institute of Immunology and Rheumatology, National Hospital, University of Oslo, Norway.
Objective:
To investigate terminal complement activation and lysis inhibitors in rheumatoid arthritis (RA).
Methods:
C5a, vitronectin and clusterin were quantitated by enzyme immunoassays in plasma and synovial fluid (SF) in RA (n = 30) and osteoarthritis (OA) (n = 11).
Results:
In RA the concentration of C5a was 3-fold increased in plasma (21.9 vs 7.2 micrograms/l) and 5-fold increased in SF (7.8 vs 1.7 micrograms/l) compared to OA. The SF/plasma ratios for C5a, vitronectin and clusterin were 0.35, 0.36 and 0.23, respectively, not significantly different in the 2 diseases.
Conclusion:
SF terminal pathway activation in RA combined with low local levels of lysis inhibitors might allow lytic or sublytic attacks on local cells, resulting in inflammation and cell damage.
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