RESUMO
PURPOSE: Rheumatoid arthritis (RA) is associated with HLA-DRB1 genes encoding a five amino acid basic motive, the shared epitope SE). Each HLA-DRB1 genotype defines a genotype specific risk of developing RA. RA is preceded by the emergence of anti citrullinated protein antibodies (ACPAs). Citrullin is a neutral version of arginin, a basic amino acid, formed after post translational modification by Peptidyl Arginyl Deiminases (PADs). HLA-DRB1 genes associated with RA are also associated with ACPAs. Two models might explain this association. Here we tested both models for prediction of HLA-DRB1 genotypic risks of developing RA. METHODS: We calculated the likelihoods for the 2 HLA-DR molecules encoded by 12 common HLA-DRB1 genotypes to bind at least one randomly chosen peptide from PAD4 or fibrinogen(native or citrullinatd) and compared them with the 12 respective HLA-DRB1genotypic risks of developing RA. RESULTS: HLA-DRB1 Genotypic risks of developing RA correlate with likelihoods of binding PAD4 peptides, not citrullinated Fibrinogen peptides. Thus, the molecular basis for the association of HLA-DR and ACPA positive RA is most likely the capability for RA associated HLA-DR molecules to bind peptides(s) from PAD4.
Assuntos
Artrite Reumatoide/imunologia , Cadeias HLA-DRB1/imunologia , Peptídeos Cíclicos/imunologia , Peptídeos/imunologia , Proteína-Arginina Desiminase do Tipo 4/imunologia , Alelos , Sequência de Aminoácidos , Artrite Reumatoide/genética , Autoanticorpos/imunologia , Autoanticorpos/metabolismo , Autoantígenos/imunologia , Autoantígenos/metabolismo , Ligação Competitiva , Citrulinação/imunologia , Epitopos/imunologia , Epitopos/metabolismo , Fibrinogênio/química , Fibrinogênio/imunologia , Fibrinogênio/metabolismo , Predisposição Genética para Doença/genética , Genótipo , Cadeias HLA-DRB1/genética , Cadeias HLA-DRB1/metabolismo , Humanos , Peptídeos/metabolismo , Peptídeos Cíclicos/metabolismo , Ligação Proteica , Proteína-Arginina Desiminase do Tipo 4/química , Proteína-Arginina Desiminase do Tipo 4/metabolismoRESUMO
Autoantibodies to citrullinated proteins (ACPAs) are present in two-thirds of patients with rheumatoid arthritis (RA). ACPAs are produced in the absence of identified T cell responses for each citrullinated protein. Peptidyl arginine deiminase 4 (PAD4), which binds proteins and citrullinates them, is the target of autoantibodies in early RA. This suggests a model for the emergence of ACPAs in the absence of detectable T cells specific for citrullinated antigens: ACPAs could arise because PADs are recognized by T cells, which help the production of autoantibodies to proteins bound by PADs, according to a "hapten/carrier" model. Here, we tested this model in normal mice. C3H are healthy mice whose IEßk chain is highly homologous to the ß1 chain HLA-DRB1*04:01, the allele most strongly associated with RA in humans. C3H mice immunized with PADs developed antibodies and T cells to PAD and IgG antibodies to citrullinated fibrinogen peptides, in the absence of a T cell response to fibrinogen. To analyze the MHC background effect on hapten/carrier immunization, we immunized DBA/2 mice (whose IEßd chain is similar to that of HLA-DRB1*04:02, an HLA-DR4 subtype not associated with RA). DBA/2 mice failed to develop antibodies to citrullinated fibrinogen peptides. Thus, T cell immunization to PAD proteins may trigger ACPAs through a hapten/carrier mechanism. This may constitute the basis for a new mouse model of ACPA-positive RA.
Assuntos
Artrite Reumatoide/imunologia , Autoanticorpos/imunologia , Autoantígenos/imunologia , Citrulinação/imunologia , Desiminases de Arginina em Proteínas/imunologia , Animais , Citrulina/metabolismo , Modelos Animais de Doenças , Fibrinogênio/imunologia , Fibrinogênio/metabolismo , Haptenos/imunologia , Humanos , Imunização/métodos , Complexo Principal de Histocompatibilidade/imunologia , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos DBA , Linfócitos T/imunologiaRESUMO
BACKGROUND: TNF weakly inducer of apoptosis (TWEAK) is member of the TNF ligand superfamily. Various data support that TWEAK produced by synovial macrophages may contribute to synovitis observed in psoriatic arthritis (PsoA). In PsoA, anti-TNF therapy has been successful in agreement with the key role of TNF in the pathogenesis and the generation by PsoA patients of anti-TNF autoantibodies referred as "beneficial autoimmunity to pro-inflammatory mediators". However, the role of TNF-alpha in the regulation of TWEAK modulation of inflammation during PsoA remains unknown. METHODS: We have studied level course during anti-TNF therapy of serum soluble TWEAK. In the same cohort, we have investigated the generation of TWEAK-binding autoantibodies by PsoA patients before and after anti-TNF therapy. RESULTS: Patients with PsoA had significantly higher serum levels of TWEAK compared with controls [respective means (±SEM) were 645 pg/ml (64) and 467 pg/ml (23); (p = 0.006)] but serum soluble TWEAK levels were not correlated with BASDAI (Spearman's coefficients <0.003, p > 0.05). Our study showed that soluble TWEAK levels were not modulated by etanercept therapy [respective Means (±SEM) were 605 (95) (week 12) and 744 (97) (week 24) pg/ml; (p > 0.23)]. Anti-TWEAK autoantibodies were detected in 9/13 (69.2 %) PsoA patients at inclusion and only in 3/57 (5.3 %) healthy blood donors (p < 0.0001). These circulating antibodies were persistent in PsoA patients and detected at similar levels during etanercept therapy. Moreover we showed that they had a down regulating effect on CCL-2 secretion by endothelial cells stimulated by rh TWEAK in vitro. CONCLUSION: Our study revealed that during psoriatic arthritis (1) serum TWEAK was up regulated and (2) TWEAK-binding autoantibodies are generated. Both parameters were not influenced by anti-TNF therapy and persisted at high levels during anti-TNF therapy. For the first time we described here TWEAK-binding IgG autoantibodies with a down regulating effect on CCL-2 secretion by endothelial cells stimulated by rh TWEAK in vitro. Finally, our results suggest that TWEAK may be involved in PsoA pathogeny. Trial registration This clinical trial was approved by the local Ethics Committee "Comité de Protection des Personnes Sud-Méditerranée V" with the registration number: 2011-002954-29, and French health minister registration number AFSSAPS A110784-42 obtained the 08/22/2011. This clinical trial is registered in Clinical trial.gov under the number: NCT02164214.
Assuntos
Artrite Psoriásica/tratamento farmacológico , Artrite Psoriásica/imunologia , Autoanticorpos/metabolismo , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fatores de Necrose Tumoral/metabolismo , Adulto , Idoso , Artrite Psoriásica/sangue , Autoanticorpos/sangue , Quimiocina CCL2/metabolismo , Estudos de Coortes , Citocina TWEAK , Regulação para Baixo , Células Endoteliais/metabolismo , Feminino , Células HEK293 , Células Endoteliais da Veia Umbilical Humana , Humanos , Masculino , Pessoa de Meia-Idade , Ligação Proteica , Fatores de Necrose Tumoral/sangueAssuntos
Anticorpos Antiproteína Citrulinada/imunologia , Artrite Reumatoide/genética , Artrite Reumatoide/imunologia , Cadeias HLA-DRB1/genética , Polimorfismo Genético , Alelos , Animais , Anticorpos Antiproteína Citrulinada/metabolismo , Colágeno/metabolismo , Epitopos/imunologia , Epitopos/metabolismo , Fibrinogênio/química , Fibrinogênio/metabolismo , Cadeias HLA-DRB1/química , Cadeias HLA-DRB1/metabolismo , Humanos , Camundongos , Ligação Proteica , Linfócitos T/imunologia , Vimentina/metabolismoAssuntos
Assistência ao Convalescente/métodos , Artrite Reumatoide/terapia , Avaliação de Resultados em Cuidados de Saúde/métodos , Autoavaliação (Psicologia) , Fatores de Tempo , Adulto , Assistência ao Convalescente/psicologia , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Índice de Gravidade de DoençaRESUMO
Objective: COVID-19 outcome may be less favourable in patients with inflammatory rheumatic and musculoskeletal diseases (RMD) receiving immunosuppressive therapy. We aimed to investigate whether RMD patients on anti-IL6 therapy prior to SARS-CoV-2 infection have less severe disease and better outcomes of COVID-19. Methods: We conducted a retrospective national, multicentre cohort study using data from the French RMD COVID-19 cohort. We compared the severity and outcome of highly suspected or confirmed COVID-19 infection in RMD patients previously treated with tocilizumab or sarilumab (anti-IL6 group) with patients who did not receive anti-IL6 therapy (no anti-IL6 group). Results: Data were collected for 1883 patients with mean age of 55.2 years [SD 16.7] and 1256 (66.7%) female. Two hundred ten (11.1%) developed severe COVID-19 and 115 (6.4%) died. After adjusting for potential confounding factors, severe COVID-19 was less frequent in the anti-IL6 group compared with the no anti-IL6 group (aOR for moderate vs. mild severity, 0.23 [95% CI, 0.10 to 0.54], p ≤ 0.01 and aOR for severe vs. mild, 0.29 [95% CI, 0.10 to 0.81], p ≤ 0.01). No significant differences were found for the evolution of COVID-19 between the anti-IL6 group and the no anti-IL6 group (aOR for recovery with sequelae vs recovery without sequelae, 0.78 [95% CI, 0.41 to 1.48] and aOR for death vs recovery without sequelae, 0.29 [95% CI, 0.07 to 1.30]). Conclusion: RMD patients receiving anti-IL6 therapy prior to SARS-CoV-2 infection have less severe forms of COVID-19. No difference was observed in COVID-19 evolution, i.e., sequelae or death, between the groups.
RESUMO
The risk to develop ACPA positive rheumatoid arthritis (RA), the most destructive type of autoimmune arthritis, is carried by HLA-DRB1 alleles containing a 5 amino acid motif: the shared epitope (SE). RA is preceded by the emergence of disease specific anti citrullinated protein antibodies (ACPA). SE positive HLA-DRB1 alleles are associated with ACPA and ACPA positive RA, not with ACPA negative RA, suggesting that ACPA contribute to the pathogenesis of RA. Understanding how HLA-DRB1 genotypes influence ACPA could lead to a curative or preventive treatment of RA. The "Shared epitope binds citrullinated peptides " hypothesis suggests that RA associated HLA-DR alleles present citrullinated peptides to T cells that help ACPA producing B cells. The "Hapten carrier model" suggests that PAD4 is the target of the T cells which help ACPA specific B cells through a hapten carrier mechanism in which PAD4 is the carrier and citrullinated peptides are the haptens. Direct binding assay of citrullinated peptides to purified HLA-DR molecules does not support the "shared epitope binds citrullinated peptides" hypothesis. The Odds Ratios to develop ACPA positive RA associated with each of 12 common HLA-DRB1 genotypes match the probability that the two HLA-DR molecules they encode can bind at least one peptide from PAD4, not from citrullinated fibrinogen. Thus, PAD4 tolerization might stop the carrier effect and switch off production of ACPA.
Assuntos
Artrite Reumatoide , Autoanticorpos , Citrulinação , Artrite Reumatoide/genética , Artrite Reumatoide/imunologia , Autoanticorpos/biossíntese , Epitopos , Cadeias HLA-DRB1/genética , Cadeias HLA-DRB1/imunologia , Haptenos/genética , Haptenos/imunologia , Humanos , Peptídeos/genética , Peptídeos/imunologia , Peptídeos Cíclicos/genética , Peptídeos Cíclicos/imunologiaRESUMO
Introduction: Psoriatic arthritis (PsA) is a chronic inflammatory disease that frequently develops in patients with psoriasis (PsO) but can also occur spontaneously. As a result, PsA diagnosis and treatment is commonly delayed, or even missed outright due to the manifold of clinical presentations that patients often experience. This inevitably results in progressive articular damage to axial and peripheral joints and entheses. As such, patients with PsA frequently experience reduced expectancy and quality of life due to disability. More recently, research has aimed to improve PsA diagnosis and prognosis by identifying novel disease biomarkers. Methods: Here, we conducted a systematic review of the published literature on candidate biomarkers for PsA diagnosis and prognosis in MEDLINE(Pubmed), EMBase and the Cochrane library with the goal to identify clinically applicable PsA biomarkers. Meta-analyses were performed when a diagnostic bone and cartilage turnover biomarker was reported in 2 or moredifferent cohorts of PsA and control. Results: We identified 1444 publications and 124 studies met eligibility criteria. We highlighted bone and cartilage turnover biomarkers, genetic markers, and autoantibodies used for diagnostic purposes of PsA, as well as acute phase reactant markers and bone and cartilage turnover biomarkers for activity or prognostic severity purposes. Serum cartilage oligometrix metalloproteinase levels were significantly increased in the PsA sera compared to Healthy Control (HC) with a standardized mean difference (SMD) of 2.305 (95%CI 0.795-3.816, p=0.003) and compared to osteoarthritis (OA) with a SMD of 0.783 (95%CI 0.015-1.551, p=0.046). The pooled serum MMP-3 levels were significantly higher in PsA patients than in PsO patients with a SMD of 0.419 (95%CI 0.119-0.719; p=0.006), but no significant difference was highlighted when PsA were compared to HC. While we did not identify any new genetic biomarkers that would be useful in the diagnosis of PsA, recent data with autoantibodies appear to be promising in diagnosis, but no replication studies have been published. Conclusion: In summary, no specific diagnostic biomarkers for PsA were identified and further studies are needed to assess the performance of potential biomarkers that can distinguish PsA from OA and other chronic inflammatory diseases.
Assuntos
Artrite Psoriásica , Osteoartrite , Psoríase , Humanos , Qualidade de Vida , Biomarcadores , Autoanticorpos , Osteoartrite/diagnósticoRESUMO
Despite introduction of biological disease modifying anti-rheumatic drugs (DMARDs) for Rheumatoid arthritis (RA) treatment, therapeutic strategies do not always lead to disease control and remission. Hence, a more efficient patient stratification and monitoring biomarkers and tools are needed to enable a more personalized medicine. We used a whole blood based functional flow cytometry assay to characterize immune cells from RA patients (treated or not), healthy donors and psoriatic arthritis (PsA) patients according to their responses to LPS and/or anti-TNFα (infliximab, IFX). Activation marker expression was measured using a 10-color flow cytometry panel following a no-wash protocol. Naïve-to-treatment RA patients had a stronger inflammatory profile in comparison to healthy donors at basal level. Higher expression of activation markers (CD69 and/or CD11b) on NK, B cells and granulocytes and lower expression of the adhesion molecule CD62L were measured on monocytes, granulocytes and B cells. After LPS, naïve RA patients' cells were less capable of regulating CD69, CD11b, CD16 or CD62L showing impaired activation capabilities. Upon LPS and IFX co-incubation, hierarchical clustering analysis showed different profiles between cohorts. We believe that this whole blood-based approach should further be assessed for RA patient characterization as it provides new perspectives for stratification and/or monitoring.
Assuntos
Antirreumáticos , Artrite Psoriásica , Artrite Reumatoide , Antirreumáticos/uso terapêutico , Artrite Psoriásica/tratamento farmacológico , Artrite Reumatoide/tratamento farmacológico , Biomarcadores/metabolismo , Citometria de Fluxo , Humanos , Lipopolissacarídeos/farmacologia , Pesquisa Translacional BiomédicaRESUMO
Psoriatic arthritis (PsA) is a type of inflammatory arthritis associated with psoriasis. HLA association studies performed in northern Europe, comparing patients with control populations, have shown that the highest risk for PsA is carried by HLA-C*06, HLA-B*57 and HLA-B*27 alleles. This retrospective association study compared HLA-A, -B, -C, and -DR alleles of 500 patients from southern France, who fulfilled the CASPAR criteria for Psoriatic Arthritis (PsA), with 2346 controls from healthy blood donors, using the chi-square test. We classified PsA patients into three different subgroups according to disease: purely axial, purely peripheral and combined axial and peripheral. The 'axial' subgroup was associated with HLA-B*27 (OR = 16.3, p = 2.7 × 10-28) and its haplotypes: HLA- B*27-C*01 (OR = 12.4, p = 1.7 × 10-12) and HLA-B*27-C*02 (OR = 8.7, p = 10 × 10-9). The 'axial and peripheral' and the 'peripheral' subgroups were associated with HLA-C*06 (respectively OR = 1.5, p = 3.6 × 10-10 and OR = 2.4, p = 3.6 × 10-12) and its haplotypes HLA-C*06-B*13 (respectively OR = 2.4, p = 1.2 × 10-6 and OR = 2.8, p = 6.4 × 10-11). This association study on a southern French PsA cohort identifies HLA-C*06 as a marker for peripheral PsA and HLA-B*27 as a marker for purely axial PsA.
Assuntos
Artrite Psoriásica , Alelos , Artrite Psoriásica/epidemiologia , Artrite Psoriásica/genética , França/epidemiologia , Predisposição Genética para Doença , Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-C/genética , Cadeias HLA-DRB1/genética , Humanos , Estudos RetrospectivosRESUMO
Objectives: Rheumatoid arthritis (RA) is associated with HLA-DRB1 genes encoding the shared epitope (SE), a 5-amino acid motive. RA is usually preceded by the emergence of anti-citrullinated protein/peptide antibodies (ACPAs). Citrulline is a neutral amino acid resulting from post-translational modification of arginine involved in peptidic bounds (arginyl residue) by PeptidylArginine Deiminases (PADs). ACPAs recognize epitopes from citrullinated human fibrin(ogen) (hFib) and can be specifically detected by the AhFibA assay. Five citrullinated peptides derived from hFib together represent almost all of the epitopes recognized by patients with ACPA-positive RA, namely: α36-50cit, α171-185cit, α501-515cit, α621-635cit, and ß60-74cit. The use of antibody fine specificities as markers of clinical phenotypes has become a major challenge. Our objective was to study whether RA clinical characteristics and HLA-DRB1 genetic background were associated with a specific reactivity against the epitopes borne by the five peptides. Methods: 184 ACPA-positive RA patients fulfilling the 2010 ACR/EULAR criteria were studied. Patient characteristics including HLA-DRB1 genotype, were collected from their medical files. Anti-CCP2 antibodies, AhFibA, and antibodies against the five citrullinated hFib (hFib-cit) peptides were analyzed by ELISA. Results: Anti-α505-515cit antibodies were associated with HLA-DRB1*04:01 (OR = 5.52 [2.00 - 13.64]; p = 0.0003). High level anti-α505-515cit antibodies were associated with rheumatoid nodules (OR = 2.71 [1.00 - 7.16], p= 0.044). Conclusion: Immune complexes containing anti-α501-515cit antibodies and rheumatoid factors might be involved in the development of rheumatoid nodules on the HLA-DRB1*04:01 background. Apheresis of these epitope-specific antibodies might be a new therapeutic opportunity for patients with rheumatoid nodules.
Assuntos
Anticorpos Antiproteína Citrulinada/imunologia , Artrite Reumatoide/imunologia , Epitopos/imunologia , Fibrina/imunologia , Cadeias HLA-DRB1/imunologia , Peptídeos/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fator Reumatoide/imunologiaRESUMO
OBJECTIVE: To assess the prevalence of axial articular manifestations (AAMs) in patients with primary Sjögren syndrome (pSS), to investigate whether these symptoms reveal an associated spondyloarthritis (SpA), and to assess their therapeutic management. METHODS: Among 148 consecutive patients with pSS fulfilling European League Against Rheumatism (EULAR)/American College of Rheumatology 2019 classification criteria followed between 2010 and 2018, we selected those who presented with AAMs. The association with SpA was retained when patients fulfilled Assessment of SpA international Society criteria. RESULTS: A total of 29 patients (20%, 28 women) with a median age of 43 years (range 15-65 yrs), were identified. The main extraglandular features were peripheral arthralgia and arthritis in 93% and 90% of patients, respectively. Positive anti-Ro/SSA (anti-SSA) antibody was reported in 62%. AAMs were inaugural in 7%, delayed from the diagnostic of pSS in 7%, and occurred concomitantly in 86% of patients. AAMs were not associated to multisystemic involvement of pSS. Radiographic sacroiliitis was mentioned in 65%, and HLA-B27 was positive in 13%. The diagnosis of SpA was retained in 23/29 patients (79%), among which 74% and 26% fulfilled psoriatic arthritis and ankylosing spondylitis criteria, respectively. There was no phenotypic difference according to the anti-SSA antibody status. With a median follow-up of 60 months (range: 5-96), 61% of patients with associated SpA required biotherapies, mainly of anti-tumor necrosis factor-α or anti-interleukin 17A molecules with a good clinical outcome in 64% and no effect on pSS. CONCLUSION: AAMs are not uncommon in patients with pSS and may reveal an associated SpA. Treatment of AAMs, especially when clearly associated with SpA, may necessitate biologics, following SpA-management therapeutic guidelines.
Assuntos
Sacroileíte , Síndrome de Sjogren , Espondilartrite , Espondilite Anquilosante , Adolescente , Adulto , Idoso , Feminino , Antígeno HLA-B27 , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome de Sjogren/complicações , Síndrome de Sjogren/epidemiologia , Espondilartrite/complicações , Espondilartrite/epidemiologia , Espondilite Anquilosante/complicações , Espondilite Anquilosante/epidemiologia , Adulto JovemRESUMO
OBJECTIVE: The presence of autoantibodies to citrullinated proteins (ACPAs) often precedes the development of rheumatoid arthritis (RA). Citrullines are arginine residues that have been modified by peptidylarginine deiminases (PADs). PAD4 is the target of autoantibodies in RA. ACPAs could arise because PAD4 is recognized by T cells, which facilitate the production of autoantibodies to proteins bound by PAD4. We previously found evidence for this hapten-carrier model in mice. This study was undertaken to investigate whether there is evidence for this model in humans. METHODS: We analyzed antibody response to PAD4 and T cell proliferation in response to PAD4 in 41 RA patients and 36 controls. We tested binding of 65 PAD4 peptides to 5 HLA-DR alleles (DRB1*04:01, *04:02, *04:04, *01:01, and *07:01) and selected 11 PAD4 peptides for proliferation studies using samples from 22 RA patients and 27 controls. Peripheral blood lymphocytes from an additional 10 RA patients and 7 healthy controls were analyzed by flow cytometry for CD3, CD4, CD154, and tumor necrosis factor expression after PAD4 stimulation. RESULTS: Only patients with RA had both antibodies and T cell responses to PAD4. T cell response to peptide 8, a PAD4 peptide, was associated with RA (P = 0.02), anti-PAD4 antibodies (P = 0.057), and the shared epitope (P = 0.05). CONCLUSION: ACPA immunity is associated with antibodies to PAD4 and T cell responses to PAD4 and PAD4 peptides. These findings are consistent with a hapten-carrier model in which PAD4 is the carrier and citrullinated proteins are the haptens.
Assuntos
Anticorpos Antiproteína Citrulinada/imunologia , Artrite Reumatoide/imunologia , Autoanticorpos/imunologia , Haptenos/imunologia , Desiminases de Arginina em Proteínas/imunologia , Alelos , Anticorpos Antiproteína Citrulinada/sangue , Artrite Reumatoide/sangue , Autoanticorpos/sangue , Autoimunidade/imunologia , Proliferação de Células , Antígenos HLA-DR/imunologia , Humanos , Proteína-Arginina Desiminase do Tipo 4/imunologia , Linfócitos T/imunologiaRESUMO
The X chromosome, hemizygous in males, contains numerous genes important to immunological and hormonal function. Alterations in X-linked gene dosage are suspected to contribute to female predominance in autoimmunity. A powerful example of X-linked dosage involvement comes from the BXSB murine lupus model, where the duplication of the X-linked Toll-Like Receptor 7 (Tlr7) gene aggravates autoimmunity in male mice. Such alterations are possible in men with autoimmune diseases. Here we showed that a quarter to a third of men with rheumatoid arthritis (RA) had significantly increased copy numbers (CN) of TLR7 gene and its paralog TLR8. Patients with high CN had an upregulated pro-inflammatory JNK/p38 signaling pathway. By fluorescence in situ hybridization, we further demonstrated that the increase in X-linked genes CN was due to the presence of an extra X chromosome in some cells. Men with RA had a significant cellular mosaicism of female (46,XX) and/or Klinefelter (47,XXY) cells among male (46,XY) cells, reaching up to 1.4% in peripheral blood. Our results present a new potential trigger for RA in men and opens a new field of investigation particularly relevant for gender-biased autoimmune diseases.
Assuntos
Artrite Reumatoide/sangue , Artrite Reumatoide/genética , Dosagem de Genes , Mosaicismo , Receptor 7 Toll-Like/genética , Receptor 8 Toll-Like/genética , Artrite Reumatoide/metabolismo , Artrite Reumatoide/patologia , Estudos de Casos e Controles , Cromossomos Humanos X/genética , Cromossomos Humanos Y/genética , Humanos , Masculino , RNA Mensageiro/genética , Transdução de Sinais , Receptor 7 Toll-Like/metabolismo , Receptor 8 Toll-Like/metabolismoRESUMO
Rheumatoid arthritis (RA) is one of the most common autoimmune diseases, with a 0.5% worldwide prevalence. The cause of RA remains unknown, however both genetic and environmental factors may contribute to its development. Among these is the Epstein-Barr virus (EBV). Here, we discuss several aspects of the close relationship between EBV and RA. Patients with RA have impaired control of EBV infection. Indeed, they have high titres of antibodies against EBV antigens. Their peripheral blood T lymphocytes are less efficient at controlling the outgrowth of EBV-infected B cells. RA patients have more EBV-infected B cells than normal controls, leading to a 10-fold systemic EBV overload. Post-transplant lymphoproliferative disorder (PTLPD) is a polyclonal EBV-positive B lymphocyte proliferation, which can evolve into an EBV-positive B cell lymphoma. RA patients also have an increased risk of developing EBV-associated lymphoproliferative disorder (LPD). Hence the need to monitor EBV load when treating RA patients with immunosuppressors. EBV, a widespread virus, highly recognized by antibodies but never eliminated, is an ideal candidate to trigger chronic immune complex disease. Anti-EBV antibody responses should be considered as one of the chronic autoantibody responses linked to the development of RA, in the same way as anti-citrullinated protein antibodies.
Assuntos
Anticorpos Antiproteína Citrulinada/imunologia , Artrite Reumatoide/epidemiologia , Artrite Reumatoide/imunologia , Infecções por Vírus Epstein-Barr/epidemiologia , Infecções por Vírus Epstein-Barr/imunologia , Herpesvirus Humano 4/patogenicidade , Fatores Etários , Artrite Reumatoide/fisiopatologia , Linfócitos B/imunologia , Comorbidade , Infecções por Vírus Epstein-Barr/fisiopatologia , Feminino , Humanos , Masculino , Prevalência , Prognóstico , Medição de Risco , Fatores Sexuais , Carga Viral/imunologiaRESUMO
OBJECTIVE: To test whether HLA-DR alleles influence the production of particular autoantibodies in rheumatoid arthritis (RA) patients, we screened synovial proteins with sera of RA patients homozygous for different HLA-DR alleles by using 2D blots. We found that sera of RA patients homozygous for HLA-DRB1*0404 recognised a 100-kDa synovial protein identified as calpastatin. We studied B and T cell epitopes on calpastatin and their association with HLA-DRB1*0404. METHODS: The frequency of positive sera in patients expressing different RA-associated HLA-DR allele combinations was calculated by inhouse ELISA using purified synovial calpastatin or calpastatin peptides encompassing the entire calpastatin protein as immunosorbent. Interaction between calpastatin peptides and HLA-DR alleles was tested by a direct binding assay. T cell responses to calpastatin were measured in RA patients and controls. RESULTS: We found that RA-associated HLA-DR alleles are associated with presence of autoantibodies to synovial calpastatin in RA patients' sera. HLA-DRB1*0404 is strongly associated with antisynovial calpastatin in RA sera. One linear B cell epitope is preferentially associated with HLA-DRB1*0404. Multiple peptides from calpastatin bind every tested HLA-DR allele associated or not with RA. Peptides from domain 1 and 4 of calpastatin are the best HLA-DR allele binders. The T cell response to calpastatin is frequent in RA patients and independent of the HLA-DR background. CONCLUSIONS: HLA-DRB1*0404 is strongly associated with anticalpastatin antibodies in rheumatoid arthritis.
Assuntos
Artrite Reumatoide/imunologia , Autoanticorpos/análise , Proteínas de Ligação ao Cálcio/imunologia , Antígenos HLA-DR/análise , Membrana Sinovial/imunologia , Alelos , Autoanticorpos/metabolismo , Linfócitos B/imunologia , Proteínas de Ligação ao Cálcio/farmacologia , Estudos de Casos e Controles , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Distribuição de Qui-Quadrado , Eletroforese em Gel Bidimensional , Ensaio de Imunoadsorção Enzimática , Epitopos , Predisposição Genética para Doença , Antígenos HLA-DR/metabolismo , Cadeias HLA-DRB1 , Humanos , Ligação Proteica , Estrutura Terciária de Proteína , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologiaRESUMO
BACKGROUND: Epstein-Barr Virus (EBV) is a widely disseminated lymphotropic herpes virus implicated in benign and malignant disorders. In transplant patients, immunosuppressive drugs (cyclosporine) diminish control of EBV replication, potentially leading to lymphoproliferative disorders (LPD). Rheumatoid arthritis (RA) patients have impaired control of EBV infection and have EBV load ten times higher than controls. As post transplant patients, patients with RA have increased risk of developing lymphomas. Immunosuppressive drugs used to treat RA (conventional disease modifying drugs cDMARDs or biologics bDMARDs) could enhance the risk of developing LPD in RA patients. We have previously shown that long term treatment with Methotrexate and/or TNF alpha antagonists does not increase EBV load in RA. Our objective was to monitor the Epstein-Barr Virus load in RA patients treated with Abatacept (CTLA4 Ig), a T cell coactivation inhibitor, and Tocilizumab, an anti IL6 receptor antibody. METHODS: EBV load in the peripheral blood mononuclear cells (PBMCs) of 55 patients under Abatacept (in 34% associated with Methotrexate) and 35 patients under Tocilizumab (in 37% associated with Methotrexate) was monitored for durations ranging from 6 months to 3 years by real time PCR. The influences of treatment duration and disease activity score 28 (DAS28) index on EBV load were analyzed. RESULTS: Abatacept did not significantly modify EBV load over time. Tocilizumab significantly diminished EBV load over time. No patient (of 90) developed EBV associated lymphoma. CONCLUSION: Long term treatment with Abatacept or Tocilizumab does not increase EBV load in the PBMNCs of patients with RA.
Assuntos
Abatacepte/uso terapêutico , Anticorpos Monoclonais Humanizados/uso terapêutico , Artrite Reumatoide/tratamento farmacológico , Herpesvirus Humano 4/fisiologia , Imunossupressores/uso terapêutico , Abatacepte/farmacologia , Adulto , Idoso , Anticorpos Monoclonais Humanizados/farmacologia , Artrite Reumatoide/patologia , Artrite Reumatoide/virologia , DNA Viral/análise , Esquema de Medicação , Quimioterapia Combinada , Feminino , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/isolamento & purificação , Humanos , Imunossupressores/farmacologia , Masculino , Metotrexato/uso terapêutico , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Carga Viral/efeitos dos fármacosRESUMO
Polymorphisms have been identified in the Xq28 locus as risk loci for rheumatoid arthritis (RA). Here, we investigated the association between three polymorphisms in the Xq28 region containing TMEM187 and IRAK1 (rs13397, rs1059703, and rs1059702) in two unstudied populations: Tunisian and French. The rs13397 G and rs1059703 T major alleles were significantly increased in RA patients (n = 408) compared with age-matched controls (n = 471) in both Tunisian and French women. These results were confirmed by a meta-analysis replication study including two independent Greek and Korean cohorts. The rs1059702 C major allele was significantly associated with RA, only with French women. In the French population, the GTC haplotype displayed a protective effect against RA, while the ATC, GCC, and GTT haplotypes conferred significant risk for RA. No association for these haplotypes was found in the Tunisian population. Our results replicated for the first time the association of the three Xq28 polymorphisms with RA risk in Tunisian and French populations and suggested that RA susceptibility is associated with TMEM187-IRAK1 polymorphisms in women. Our data further support the involvement of X chromosome in RA susceptibility and evidence ethnicities differences that might be explained by differences in the frequencies of SE HLA-DRB1 alleles between both populations.
Assuntos
Artrite Reumatoide/etnologia , Artrite Reumatoide/genética , Cromossomos Humanos X/genética , Predisposição Genética para Doença , Quinases Associadas a Receptores de Interleucina-1/genética , Proteínas de Membrana/genética , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Alelos , Artrite Reumatoide/epidemiologia , Suscetibilidade a Doenças , Feminino , França/epidemiologia , Geografia , Antígenos HLA-DR/genética , Cadeias HLA-DRB1 , Haplótipos/genética , Humanos , Metanálise como Assunto , Pessoa de Meia-Idade , Tunísia/epidemiologiaRESUMO
OBJECTIVE: Rheumatoid arthritis (RA)-associated autoantibodies include those directed at the kinase site of BRAF (v-Raf murine sarcoma viral oncogene homolog B1), a serine-threonine kinase involved in the MAPK signaling pathway. To understand anti-BRAF immunization, we sought to identify BRAF mutations in the peripheral blood lymphocytes (PBLs) of patients with RA. METHODS: We first cloned the major BRAF region known for mutations in the pCR2.1 vector, using genomic DNA from the PBLs of 8 RA patients. For each patient, 100 clones were sequenced. In 5 of 8 patients, we detected a new BRAF mutation in 1 clone. The frequency of this new mutation was evaluated by droplet digital polymerase chain reaction in PBLs from RA patients and controls. To test whether p.Val600Ala influences the kinase activity of BRAF, we developed an in vitro assay based on phosphorylation of MEK-1, a major BRAF substrate. RESULTS: A BRAF mutation, p.Val600Ala, was identified in 1 of 8,000 PBLs and 1 of 6,000 T lymphocytes from RA patients and in 1 of 12,500 PBLs and 1 of 12,500 T lymphocytes from controls. The BRAF p.Val600Ala mutation was not correlated with the presence of anti-BRAF autoantibodies. The p.Val600Ala mutation activated phosphorylation of MEK-1 in vitro. CONCLUSION: Most RA patients have a p.Val600Ala mutation in the BRAF gene. This mutation activates the kinase activity of BRAF. The p.Val600Ala mutation could activate the MAPK pathway, leading to the activation of T lymphocytes.