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- Ge, Changrong, et al.
(författare)
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Structural Basis of Cross-Reactivity of Anti-Citrullinated Protein Antibodies
- 2019
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Ingår i: Arthritis & Rheumatology. - : WILEY. - 2326-5191 .- 2326-5205. ; 71:2, s. 210-221
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Tidskriftsartikel (refereegranskat)abstract
- Objective Anti-citrullinated protein antibodies (ACPAs) develop many years before the clinical onset of rheumatoid arthritis (RA). This study was undertaken to address the molecular basis of the specificity and cross-reactivity of ACPAs from patients with RA. Methods Antibodies isolated from RA patients were expressed as monoclonal chimeric antibodies with mouse Fc. These antibodies were characterized for glycosylation using mass spectrometry, and their cross-reactivity was assessed using Biacore and Luminex immunoassays. The crystal structures of the antigen-binding fragment (Fab) of the monoclonal ACPA E4 in complex with 3 different citrullinated peptides were determined using x-ray crystallography. The prevalence of autoantibodies reactive against 3 of the citrullinated peptides that also interacted with E4 was investigated by Luminex immunoassay in 2 Swedish cohorts of RA patients. Results Analysis of the crystal structures of a monoclonal ACPA from human RA serum in complex with citrullinated peptides revealed key residues of several complementarity-determining regions that recognized the citrulline as well as the neighboring peptide backbone, but with limited contact with the side chains of the peptides. The same citrullinated peptides were recognized by high titers of serum autoantibodies in 2 large cohorts of RA patients. Conclusion These data show, for the first time, how ACPAs derived from human RA serum recognize citrulline. The specific citrulline recognition and backbone-mediated interactions provide a structural explanation for the promiscuous recognition of citrullinated peptides by RA-specific ACPAs.
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| 4. |
- Rönnelid, Johan, et al.
(författare)
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Antikroppar mot citrullinerade proteiner - genombrott i reumatologisk diagnostik
- 2004
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Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 101:50, s. 4092-4096
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Forskningsöversikt (refereegranskat)abstract
- Antibodies directed against citrullinated proteins (anti-CP) constitute a newly defined group of autoantibodies with very high diagnostic specificity for rheumatoid arthritis (RA). The most recently developed assays have a sensitivity comparable to that of traditional tests for Rheumatoid Factor (RF). Due to its considerably higher specificity, the authors recommend that anti-CP antibody analysis should replace the RF test in primary healthcare when investigating cases of clinically suspect RA.
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| 5. |
- Svärd, Anna, et al.
(författare)
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Associations to smoking and shared epitope differ between IgA and IgG class antibodies to cyclic citrullinated peptides in early rheumatoid arthritis
- 2015
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Ingår i: Arthritis & Rheumatology. - : Wiley-Blackwell. - 2326-5191 .- 2326-5205. ; 67:8, s. 2032-2037
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Tidskriftsartikel (refereegranskat)abstract
- Background Smoking and HLA-DRB1/shared epitope (SE) are well-known interacting risk factors for developing rheumatoid arthritis (RA) with IgG anticitrullinated protein/peptide antibodies (ACPA). It remains unknown to what extent SE-genes and smoking associate with mucosal immune responses.Objectives This study was done to explore relations between cigarette smoking habits and SE versus circulating IgA and IgG anti-cyclic citrullinated peptide antibodies (anti-CCP) among early RA patients.Methods Patients from two early-RA cohorts were analysed, EIRA-1 (n=1663) and TIRA-2 (n=199). The patients were grouped into four subsets based on anti-CCP: IgG-/IgA-, IgG-/IgA+, IgG+/IgA- and IgG+/IgA+. Interaction between smoking and SE was calculated by the attributable proportion due to deviation from additivity. Analyzed controls (n=1100) were randomly selected from the EIRA-1 study base.Results Anti-CCP occurrence was similar in the two cohorts. Only in EIRA was IgA anti-CCP detected alone in a minority of cases (3%). Smoking was significantly overrepresented among IgA anti-CCP+ patients with or without IgG-class anti-CCP, but not with IgG anti-CCP alone. Presence of SE genes was overrepresented among IgG anti-CCP+ patients with or without IgA-class anti-CCP, but not with IgA anti-CCP alone. Smoking and SE interacted regarding the risk of IgG+/IgA+ RA (AP=0.5, 95 % CI=0.4-0.6), whereas no significant interaction was observed regarding IgG-/IgA+ or IgG+/IgA- RA.Conclusions Association between cigarette smoking and anti-CCP is limited to cases with IgA-class antibodies in addition to IgG anti-CCP. This suggests a causal relation between chronic mucosal irritation/inflammation, induction of a systemic IgA anti-CCP response and subsequent development of RA.
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