Autoimmune Response to Post-Translationally Modified (Citrullinated) Proteins: Prime Suspect in the Pathophysiology of Rheumatoid Arthritis

Author(s):  
Mireille Sebbag ◽  
Cyril Clavel ◽  
Leonor Nogueira ◽  
Jacques Arnaud ◽  
Guy Serre
2013 ◽  
Vol 73 (3) ◽  
pp. 580-586 ◽  
Author(s):  
Paola de Pablo ◽  
Thomas Dietrich ◽  
Iain L C Chapple ◽  
Michael Milward ◽  
Muslima Chowdhury ◽  
...  

BackgroundStudies suggest that periodontitis may be a risk factor for rheumatoid arthritis (RA). The purpose of this study was to determine whether periodontitis is associated with autoantibodies characteristic of RA.MethodsSerum samples were tested for anti-cyclic citrullinated peptide (CCP), anti-mutated citrullinated vimentin (MCV), anti-citrullinated α-enolase peptide-1 (CEP-1), anti-citrullinated vimentin (cit-vim), anti-citrullinated fibrinogen (cit-fib) and their uncitrullinated forms anti-CParg (negative control for anti-CCP), anti-arginine-containing α-enolase peptide-1 (REP-1), anti-vimentin and anti-fibrinogen antibodies in patients with and without periodontitis, none of whom had RA.ResultsPeriodontitis, compared with non-periodontitis, was associated with a normal frequency of anti-CCP and anti-MCV (∼1%) but a higher frequency of positive anti-CEP-1 (12% vs 3%; p=0.02) and its uncitrullinated form anti-REP-1 (16% vs 2%; p<0.001). Positive antibodies against uncitrullinated fibrinogen and CParg were also more common among those with periodontitis compared to non-periodontitis patients (26% vs 3%; p<0.001, and 9% vs 3%; p=0.06). After adjusting for confounders, patients with periodontitis had 43% (p=0.03), 71% (p=0.002) and 114% (p<0.001) higher anti-CEP-1, anti-REP-1 and anti-fibrinogen titres, compared with non-periodontitis. Non-smokers with periodontitis, compared with non-periodontitis, had significantly higher titres of anti-CEP-1 (103%, p<0.001), anti-REP-1 (91%, p=0.001), anti-vimentin (87%, p=0.002), and anti-fibrinogen (124%, p<0.001), independent of confounders, confirming that the autoantibody response in periodontitis was not due to smoking.ConclusionsWe have shown that the antibody response in periodontitis is predominantly directed to the uncitrullinated peptides of the RA autoantigens examined in this study. We propose that this loss of tolerance could then lead to epitope spreading to citrullinated epitopes as the autoimmune response in periodontitis evolves into that of presymptomatic RA.


2004 ◽  
Vol 71 (6) ◽  
pp. 493-502 ◽  
Author(s):  
Mireille Sebbag ◽  
Sabine Chapuy-Regaud ◽  
Isabelle Auger ◽  
Elisabeth Petit-Texeira ◽  
Cyril Clavel ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thomas B. G. Poulsen ◽  
Dres Damgaard ◽  
Malene M. Jørgensen ◽  
Ladislav Senolt ◽  
Jonathan M. Blackburn ◽  
...  

AbstractThe presence or absence of autoantibodies against citrullinated proteins (ACPAs) distinguishes two main groups of rheumatoid arthritis (RA) patients with different etiologies, prognoses, disease severities, and, presumably, disease pathogenesis. The heterogeneous responses of RA patients to various biologics, even among ACPA-positive patients, emphasize the need for further stratification of the patients. We used high-density protein array technology for fingerprinting of ACPA reactivity. Identification of the proteome recognized by ACPAs may be a step to stratify RA patients according to immune reactivity. Pooled plasma samples from 10 anti-CCP-negative and 15 anti-CCP-positive RA patients were assessed for ACPA content using a modified protein microarray containing 1631 different natively folded proteins citrullinated in situ by protein arginine deiminases (PADs) 2 and PAD4. IgG antibodies from anti-CCP-positive RA plasma showed high-intensity binding to 87 proteins citrullinated by PAD2 and 99 proteins citrullinated by PAD4 without binding significantly to the corresponding native proteins. Curiously, the binding of IgG antibodies in anti-CCP-negative plasma was also enhanced by PAD2- and PAD4-mediated citrullination of 29 and 26 proteins, respectively. For only four proteins, significantly more ACPA binding occurred after citrullination with PAD2 compared to citrullination with PAD4, while the opposite was true for one protein. We demonstrate that PAD2 and PAD4 are equally efficient in generating citrullinated autoantigens recognized by ACPAs. Patterns of proteins recognized by ACPAs may serve as a future diagnostic tool for further subtyping of RA patients.


2014 ◽  
Author(s):  
Gary S. Firestein ◽  
Anna-Karin H. Ekwall

Rheumatoid arthritis (RA) is among the most common forms of chronic inflammatory arthritis. It affects approximately 1% of adults and is two to three times more prevalent in women than in men. There are no specific laboratory tests for RA; diagnosis depends on a constellation of signs and symptoms that can be supported by serology and radiographs. The disease evolves over many years as a consequence of repeated environmental stress causing inflammation and immune activation followed by a breakdown of tolerance in individuals with a specific genetic background. This review describes the definition of RA; its etiology, including genetics, infections, the role of smoking and citrullination of proteins, and epigenetic mechanisms; and its pathogenesis, including synovial histopathology, bone and cartilage damage, adaptive and innate immunity, and the role of cytokines and intracellular signaling. Tables include the 1987 American Rheumatism Association criteria for the classification of RA and the 2010 American College of Rheumatology/European League Against Rheumatism classification for RA. Figures show citrullinated proteins in airway cells, a section of a proliferative synovium from a patient with a classic RA, and scalloped regions of erosion at the junction between a proliferative inflamed rheumatoid synovium and the bone. This review contains 3 highly rendered figures, 2 tables, and 71 references.


2010 ◽  
Vol 38 (3) ◽  
pp. 419-428 ◽  
Author(s):  
DRAGAN V. JOVANOVIC ◽  
LAURENCE BOUMSELL ◽  
ARMAND BENSUSSAN ◽  
XAVIER CHEVALIER ◽  
ARTURO MANCINI ◽  
...  

Objective.It was recently reported that CD101 surface expression discriminates potency among CD4+CD25+ FoxP3+ regulatory T cells in the mouse. We investigated whether CD101 may also have a role in the suppressor function of regulatory T cells in humans given that the latter population may affect the autoimmune response in patients with rheumatoid arthritis (RA).Methods.Sorted T cells and monocyte/macrophage cell populations were analyzed by flow cyto metry using conjugated antibodies specific for cell-surface markers. T cell proliferation assays were conducted by [3H]thymidine incorporation and CD8highcytotoxicity measurements by Cyto-Scan-LDH cytotoxicity assays. ELISA were used to measure cytokines in cell culture supernatants and Western blotting was performed for profiling mitogen-activated protein (MAP) kinase activation using specific antiphospholipid antibodies.Results.CD101 expression coincided with PMA-induced monocyte/leukocyte lineage differentiation. CD8highCD101− T cells exhibited greater cytotoxic activity than CD8highCD101+ T cells, while no difference was observed between CD4CD25highCD101+ and CD4CD25highCD101− Treg inhibitory activity through responder T cells. LPS-induced proinflammatory cytokine production and p38 MAP kinase activation were made possible by ligation of CD101 with an anti-CD101 antibody F(ab’)2fragment.Conclusion.These results suggested a modulatory/coregulatory function of CD101 in the human immune system, in contrast to murine models, in which CD101 surface expression discriminates potency among FoxP3+ regulatory T cells. Cytotoxic CD8highCD101+ T cells were markedly less cytotoxic than CD8highT cells negative for the CD101 antigen and were conspicuously downregulated in patients with RA, suggesting a possible role for CD101 expression and function in the control of certain manifestations of RA pathology.


Cells ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 657 ◽  
Author(s):  
Francesco Carubbi ◽  
Alessia Alunno ◽  
Roberto Gerli ◽  
Roberto Giacomelli

Post-translational modifications (PTM) are chemical changes mostly catalyzed by enzymes that recognize specific target sequences in specific proteins. These modifications play a key role in regulating the folding of proteins, their targeting to specific subcellular compartments, their interaction with ligands or other proteins, and eventually their immunogenic properties. Citrullination is the best characterized PTM in the field of rheumatology, with antibodies anticyclic citrullinated peptides being the gold standard for the diagnosis of rheumatoid arthritis (RA). In recent years, growing evidence supports not only that a wide range of proteins are subject to citrullination and can trigger an autoimmune response in RA, but also that several other PTMs such as carbamylation and acetylation occur in patients with this disease. This induces a wide spectrum of autoantibodies, as biomarkers, with different sensitivity and specificity for diagnosis, which may be linked to peculiar clinical manifestations and/or response to treatment. The purpose of this review article is to critically summarize the available literature on antibodies against post-translationally modified proteins, in particular antibodies against citrullinated proteins (ACPA) and antibodies against modified proteins (AMPA), and outline their diagnostic and prognostic role to be implemented in clinical practice for RA patients.


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