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- Sohrabian, Azita, et al.
(author)
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Number of individual ACPA reactivities in synovial fluid immune complexes, but not serum anti-CCP2 levels, associate with inflammation and joint destruction in rheumatoid arthritis
- 2018
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In: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 77:9, s. 1345-1353
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Journal article (peer-reviewed)abstract
- Introduction: Individual patients with rheumatoid arthritis (RA) show divergent specific anti-citrullinated protein/peptide antibodies (ACPA) patterns, but hitherto no individual ACPA specificity has consistently been linked to RA pathogenesis. ACPA are also implicated in immune complexes (IC)-associated joint pathology, but until now, there has been no method to investigate the role of individual ACPA in RA IC formation and IC-associated pathogenesis.Methods: We have developed a new technique based on IC binding to C1q-coated magnetic beads to purify and solubilise circulating IC in sera and synovial fluids (SF) from 77 patients with RA. This was combined with measurement of 19 individual ACPA in serum, SF and in the IC fractions from serum and SF. We investigated whether occurrence of individual ACPA as well as number of ACPA in these compartments was related to clinical and laboratory measures of disease activity and inflammation.Results: The majority of individual ACPA reactivities were enriched in SF as compared with in serum, and levels of ACPA in IC were regulated independently of levels in serum and SF. No individual ACPA reactivity in any compartment showed a dominating association to clinical and laboratory measures of disease activity and severity. Instead, the number of individual ACPA reactivities in the IC fraction from SF associated with a number of markers of joint destruction and inflammation.Conclusions: Our data highlight the polyclonality of ACPA in joint IC and the possibility that a broad ACPA repertoire in synovial fluid IC might drive the local inflammatory and matrix-degrading processes in joints, in analogy with antibody-induced rodent arthritis models.
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- Weitoft, Tomas, et al.
(author)
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Cathepsin S and cathepsin L in serum and synovial fluid in rheumatoid arthritis with and without autoantibodies
- 2015
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In: Rheumatology. - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 54:10, s. 1923-1928
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Cathepsin S and cathepsin L are endosomal proteolytic enzymes involved in the degradation of extracellular matrixes, angiogenesis and antigen presentation. Cathepsins could thus play several roles in the disease process of RA. The aim of this study was to examine differences in cathepsin S and cathepsin L levels in serum and SF of RA patients with and without ACPA and RF.METHODS: In this study 121 patients with RA and clinical signs of knee synovitis were recruited. Patient characteristics were collected and matched samples of serum and SF were analysed for cathepsin S, cathepsin L, ACPA, IgA and IgM RF, CRP and MMP3.RESULTS: SF levels of cathepsin L, cathepsin S and MMP3 were significantly higher than in serum. Serum levels of both cathepsins were significantly higher in patients with ACPA, IgM-RF and IgA-RF compared with patients without these antibodies. SF levels of both cathepsins correlated with DAS28 and CRP in ACPA- and RF-positive but not in seronegative patients.CONCLUSION: The differences in cathepsin S and cathepsin L between RA patients with and without autoantibodies indicate that these cathepsins have a specific role in the disease process of seropositive RA. In this phenotype, cathepsin serum levels may reflect the autoimmune activity, whereas the levels in SF may reflect the local inflammatory and matrix degrading process in the joint.
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