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- Gerlag, Danielle M., et al.
(författare)
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EULAR recommendations for terminology and research in individuals at risk of rheumatoid arthritis : report from the Study Group for Risk Factors for Rheumatoid Arthritis
- 2012
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 71:5, s. 638-641
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Tidskriftsartikel (refereegranskat)abstract
- The Study Group for Risk Factors for Rheumatoid Arthritis was established by the EULAR Standing Committee on Investigative Rheumatology to facilitate research into the preclinical and earliest clinically apparent phases of rheumatoid arthritis (RA). This report describes the recommendation for terminology to be used to define specific subgroups during different phases of disease, and defines the priorities for research in this area. Terminology was discussed by way of a three-stage structured process: A provisional list of descriptors for each of the possible phases preceding the diagnosis of RA were circulated to members of the study group for review and feedback. Anonymised comments from the members on this list were fed back to participants before a 2-day meeting. 18 participants met to discuss these data, agree terminologies and prioritise important research questions. The study group recommended that, in prospective studies, individuals without RA are described as having: genetic risk factors for RA; environmental risk factors for RA; systemic autoimmunity associated with RA; symptoms without clinical arthritis; unclassified arthritis; which may be used in a combinatorial manner. It was recommended that the prefix 'pre-RA with:' could be used before any/any combination of the five points above but only to describe retrospectively a phase that an individual had progressed through once it was known that they have developed RA. An approach to dating disease onset was recommended. In addition, important areas for research were proposed, including research of other tissues in which an adaptive immune response may be initiated, and the identification of additional risk factors and biomarkers for the development of RA, its progression and the development of extra-articular features. These recommendations provide guidance on approaches to describe phases before the development of RA that will facilitate communication between researchers and comparisons between studies. A number of research questions have been defined, requiring new cohorts to be established and new techniques to be developed to image and collect material from different sites.
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| 2. |
- Hermansson, Monika, et al.
(författare)
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MS analysis of rheumatoid arthritic synovial tissue identifies specific citrullination sites on fibrinogen.
- 2010
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Ingår i: Proteomics - Clinical Applications. - : Wiley. - 1862-8354 .- 1862-8346. ; 4:5, s. 511-518
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Citrullination is a post-translational modification of arginine residues to citrulline catalyzed by peptidyl arginine deiminases. Induced expression of citrullinated proteins are frequently detected in various inflammatory states including arthritis; however, direct detection of citrullination in arthritic samples has not been successfully performed in the past. Experimental design Citrullination of human fibrinogen, a candidate autoantigen in arthritis, was studied. Accurate identification of citrullinated fibrinogen peptides from rheumatoid arthritis synovial tissue specimens was performed using accurate mass and retention time analysis. Results A peptide with the sequence ESSSHHPGIAEFPSRGK corresponding to amino acids 559-575 of fibrinogen a-chain was identified to be citrullinated with an occupancy rate between 1.4 and 2.5%. Citrullination of the peptide KREEAPSLRPAPPPISGGGYRARPAK corresponding to amino acids 52-77 of the fibrinogen beta-chain was identified with an occupancy rate of 1.2%. Conclusions and clinical relevance We report a proof of principle study for the identification of citrullinated proteins and within them, identification of citrullination sites and quantification of their occupancies in synovial tissue from rheumatoid arthritis patients using high-resolution MS. Detailed studies on which molecules are citrullinated in arthritis can provide information about their role in immune regulation and serve as novel biomarkers and potentially even as therapeutic targets.
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| 6. |
- Laki, Judit, et al.
(författare)
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Very high levels of anti-citrullinated protein antibodies are associated with HLA-DRB1*15 non-shared epitope allele in patients with rheumatoid arthritis
- 2012
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 64:7, s. 2078-2084
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Tidskriftsartikel (refereegranskat)abstract
- Objective Production of anticitrullinated protein antibodies (ACPAs) is an important biomarker for rheumatoid arthritis (RA). We undertook this study to determine whether genetic factors (HLADRB1 alleles) are associated with extreme ACPA levels in individuals with ACPA-positive RA, and to ascertain whether there are any phenotypic characteristics associated with these subgroups of RA. Methods HLADRB1 allelic groups were genotyped in 1,073 ACPA-positive RA patients from the Swedish Epidemiological Investigation of Rheumatoid Arthritis study. We found that 283 patients (26.4%) had high ACPA levels (defined as >1,500 units/ml using the Euro-Diagnostica anti-CCP2 test), while the rest of the patients had moderate ACPA levels and served as the comparison group. A replication group consisted of 235 RA patients. Results No significant differences in baseline disease activity were observed between patients with high and those with moderate ACPA levels. However, the HLADRB1*15 allele was associated with high ACPA levels (P = 0.0002). A similar trend was detected in HLADRB1*15positive patients in the replication cohort, with meta-analysis of the discovery and replication cohorts demonstrating an overall effect of HLADRB1*15 on development of high ACPA levels in both the discovery and replication cohorts (P < 0.0001 by Mantel-Haenszel test with a fixed-effects model). Conclusion Our data indicate that HLADRB1*15 may promote the production of high ACPA levels. Due to the high value of ACPA level scores in the 2010 American College of Rheumatology/European League Against Rheumatism classification criteria for RA, the presence of HLADRB1*15 may, at least in part, contribute to fulfilling the criteria for RA. This illustrates the complex nature of the genetic regulation of ACPA levels. Additional mechanistic studies of the regulation of ACPAs and ACPA-positive RA are pending.
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| 7. |
- Ossipova, Elena, et al.
(författare)
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Affinity purified anti-citrullinated protein/peptide antibodies target antigens expressed in the rheumatoid joint
- 2014
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Ingår i: Arthritis Research & Therapy. - London : BioMed Central (BMC). - 1478-6362 .- 1478-6354. ; 16:4
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: A major subset of patients with rheumatoid arthritis (RA) is characterized by the presence of circulating autoantibodies directed to citrullinated proteins/peptides (ACPAs). These autoantibodies, which are commonly detected by using an enzyme-linked immunosorbent assay (ELISA) based on synthetic cyclic citrullinated peptides (CCPs), predict clinical onset and a destructive disease course. In the present study, we have used plasma and synovial fluids from patients with RA, for the affinity purification and characterization of anti-CCP2 reactive antibodies, with an aim to generate molecular tools that can be used in vitro and in vivo for future investigations into the pathobiology of the ACPA response. Specifically, this study aims to demonstrate that the surrogate marker CCP2 can capture ACPAs that bind to autoantigens expressed in vivo in the major inflammatory lesions of RA (that is, in the rheumatoid joint). METHODS: Plasma (n = 16) and synovial fluid (n = 26) samples were collected from RA patients with anti-CCP2 IgG levels of above 300 AU/mL. Total IgG was isolated on Protein G columns and subsequently applied to CCP2 affinity columns. Purified anti-CCP2 IgG was analyzed for reactivity and specificity by using the CCPlus(R) ELISA, in-house peptide ELISAs, Western blot, and immunohisto-/immunocytochemistry. RESULTS: Approximately 2% of the total IgG pool in both plasma and synovial fluid was CCP2-reactive. Purified anti-CCP2 reactive antibodies from different patients showed differences in binding to CCP2 and differences in binding to citrullinated peptides from alpha-enolase, vimentin, fibrinogen, and collagen type II, illustrating different ACPA fine-specificity profiles. Furthermore, the purified ACPA bound not only in vitro citrullinated proteins but, more importantly, in vivo-generated epitopes on synovial fluid cells and synovial tissues from patients with RA. CONCLUSIONS: We have isolated ACPAs from plasma and synovial fluid and demonstrated that the CCP2 peptides, frequently used in diagnostic ELISAs, de facto act as surrogate antigens for at least four different, well-characterized, largely non-cross-reactive, ACPA fine specificities. Moreover, we have determined the concentration and proportion of CCP2-reactive IgG molecules in rheumatoid plasma and synovial fluid, and we have shown that the purified ACPAs can be used to detect both in vitro- and in vivo-generated citrullinated epitopes by various techniques. We anticipate that these antibodies will provide us with new opportunities to investigate the potential pathogenic effects of human ACPAs. © 2014 Ossipova et al.; licensee BioMed Central Ltd.
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