The molecular basis underlying T cell specificity towards citrullinated epitopes presented by HLA-DR4.

CD4+ T cells recognising citrullinated self-epitopes presented by HLA-DRB1 bearing the shared susceptibility epitope (SE) are implicated in rheumatoid arthritis (RA). However, the underlying T cell receptor (TCR) determinants of epitope specificity towards distinct citrullinated peptide antigens, including vimentin-64cit59-71 and α-enolase-15cit10-22 remain unclear. Using HLA-DR4-tetramers, we examine the T cell repertoire in HLA-DR4 transgenic mice and observe biased TRAV6 TCR gene usage across these two citrullinated epitopes which matches with TCR bias previously observed towards the fibrinogen ß-74cit69-81 epitope. Moreover, shared TRAV26-1 gene usage is evident in four α-enolase-15cit10-22 reactive T cells in three human samples. Crystal structures of mouse TRAV6+ and human TRAV26-1+ TCR-HLA-DR4 complexes presenting vimentin-64cit59-71 and α-enolase-15cit10-22, respectively, show three-way interactions between the TCR, SE, citrulline, and the basis for the biased selection of TRAV genes. Position 2 of the citrullinated epitope is a key determinant underpinning TCR specificity. Accordingly, we provide a molecular basis of TCR specificity towards citrullinated epitopes.

The peculiar features, diversity and impact of citrulline-reactive autoantibodies.

Since entering the stage 25 years ago as a highly specific serological biomarker for rheumatoid arthritis, anti-citrullinated protein antibodies (ACPAs) have been a topic of extensive research. This hallmark B cell response arises years before disease onset, displays interpatient autoantigen variability, and is associated with poor clinical outcomes. Technological and scientific advances have revealed broad clonal diversity and intriguing features including high levels of somatic hypermutation, variable-domain N-linked glycosylation, hapten-like peptide interactions, and clone-specific multireactivity to citrullinated, carbamylated and acetylated epitopes. ACPAs have been found in different isotypes and subclasses, in both circulation and tissue, and are secreted by both plasmablasts and long-lived plasma cells. Notably, although some disease-promoting features have been reported, results now demonstrate that certain monoclonal ACPAs therapeutically block arthritis and inflammation in mouse models. A wealth of functional studies using patient-derived polyclonal and monoclonal antibodies have provided evidence for pathogenic and protective effects of ACPAs in the context of arthritis. To understand the roles of ACPAs, one needs to consider their immunological properties by incorporating different facets such as rheumatoid arthritis B cell biology, environmental triggers and chronic antigen exposure. The emerging picture points to a complex role of citrulline-reactive autoantibodies, in which the diversity and dynamics of antibody clones could determine clinical progression and manifestations.

Determinación de anticuerpos anti-proteínas citrulinadas / No disponible

No disponible

Anticuerpo anticitrulina y manifestaciones extra articulares en artritis reumatoidea / Anticitrulin antibody and the extra-articular manifestations in rheumatoid arthritis

Los pacientes con artritis reumatidea (AR) pueden desarrollar manifestaciones extra articulares (MExA), relacionadas a su morbi-mortalidad. Los anticuerpos anti-péptidos citrulinados cíclicos (ACCP) son específicos para la AR y estan relacionados con el daño articular; y podrían tener rol patogénico en las MExA. Nuestro objetivo fue determinar la relación entre los anticuerpos ACCP y MExA en pacientes con AR. Se incluyeron 74 pacientes con diagnóstico de AR (ACR 1987) mayores de 18 años, de más de 6 meses de evolución, con MExA, y un control apareado por sexo y edad sin MExA por cada paciente. Las variables demográficas, clínicas y de laboratorio se compararon con test t, chi cuadrado o Mann-Whitney. Se realizó análisis multivariado; p ≤ 0.05. Los pacientes con MExA presentaron mayor título de anticuerpo ACCP (116 vs. 34, p < 0.01) y de factor reumatoideo (FR) (108 vs. 34.5, p < 0.01). En el análisis multivariado hubo asociación entre la presencia de MExA y tabaquismo activo (p = 0.02, OR: 3.78, IC 95%: 1.17-12.2), FR positivo (p = 0.04, OR: 3.23, IC95%: 1.04-11.8) y anticuerpo ACCP positivo (p = 0.04, OR: 3.23, IC 95%: 1.04-10). Presentaron mayor título de anticuerpo ACCP que los controles los pacientes con xerostomía (109 vs. 34, p = 0.04), xeroftalmia (150 vs. 34, p < 0.01), nódulos sub-cutáneos (NSC) (141 vs. 34, p < 0.01) y fibrosis pulmonar (158 vs. 34, p = 0.04). En conclusión, el anticuerpo ACCP positivo, el FR positivo y el tabaquismo activo fueron factores de riesgo independientes para el desarrollo de MExA.

A large proportion of rheumatoid arthritis (RA) patients develop extra-articular manifestations (EAM), which are associated with morbidity and early mortality. Anti cyclic citrullinated peptide (ACCP) antibody has proven to be highly specific for the diagnosis of RA, associated with severe joint damage and may have some role in the pathogenesis of EAM. The aim of this study was to determine the relationship between ACCP antibody and the presence of EAM in RA patients. Seventy four RA patients (ACR 1987) with EAM, > 18 years, more than 6 months duration were included, and an EAM free control, matched by sex and age, for each patient. Demographic, clinical and laboratory variables were compared using t-test, chi-square or Mann-Whitney test. Multivariate analysis was performed: p ≤ 0.05. Patients with EAM presented a greater value of ACCP antibody (116 vs. 34, p < 0.01) and rheumatoid factor (108 vs. 34.5, p < 0.01). Independent association with current smoking habit (p = 0.02, OR = 3.78, 95%: 1.17-12.2), RF positive (p = 0.04, OR 3.23, CI 95%: 1.04 to 11.8) and ACCP antibody positive (p = 0.04, OR 3.23, 95% CI: 1.04-10) was found. The patients with xerostomia (109 vs. 34, p = 0.04), xerophthalmia (150 vs. 34, p < 0.01), subcutaneous nodules (141 vs. 34, p < 0.01) and pulmonary fibrosis (158 vs. 34, p = 0.04) had a higher degree of the ACCP antibody, than controls. In conclusion, ACCP antibody positive, RF positive and smoking were independent risk factors for the development of MEXA.

Anticuerpo anticitrulina y manifestaciones extra articulares en artritis reumatoidea / Anticitrulin antibody and the extra-articular manifestations in rheumatoid arthritis

Los pacientes con artritis reumatidea (AR) pueden desarrollar manifestaciones extra articulares (MExA), relacionadas a su morbi-mortalidad. Los anticuerpos anti-péptidos citrulinados cíclicos (ACCP) son específicos para la AR y estan relacionados con el daño articular; y podrían tener rol patogénico en las MExA. Nuestro objetivo fue determinar la relación entre los anticuerpos ACCP y MExA en pacientes con AR. Se incluyeron 74 pacientes con diagnóstico de AR (ACR 1987) mayores de 18 años, de más de 6 meses de evolución, con MExA, y un control apareado por sexo y edad sin MExA por cada paciente. Las variables demográficas, clínicas y de laboratorio se compararon con test t, chi cuadrado o Mann-Whitney. Se realizó análisis multivariado; p ≤ 0.05. Los pacientes con MExA presentaron mayor título de anticuerpo ACCP (116 vs. 34, p < 0.01) y de factor reumatoideo (FR) (108 vs. 34.5, p < 0.01). En el análisis multivariado hubo asociación entre la presencia de MExA y tabaquismo activo (p = 0.02, OR: 3.78, IC 95%: 1.17-12.2), FR positivo (p = 0.04, OR: 3.23, IC95%: 1.04-11.8) y anticuerpo ACCP positivo (p = 0.04, OR: 3.23, IC 95%: 1.04-10). Presentaron mayor título de anticuerpo ACCP que los controles los pacientes con xerostomía (109 vs. 34, p = 0.04), xeroftalmia (150 vs. 34, p < 0.01), nódulos sub-cutáneos (NSC) (141 vs. 34, p < 0.01) y fibrosis pulmonar (158 vs. 34, p = 0.04). En conclusión, el anticuerpo ACCP positivo, el FR positivo y el tabaquismo activo fueron factores de riesgo independientes para el desarrollo de MExA.(AU)

A large proportion of rheumatoid arthritis (RA) patients develop extra-articular manifestations (EAM), which are associated with morbidity and early mortality. Anti cyclic citrullinated peptide (ACCP) antibody has proven to be highly specific for the diagnosis of RA, associated with severe joint damage and may have some role in the pathogenesis of EAM. The aim of this study was to determine the relationship between ACCP antibody and the presence of EAM in RA patients. Seventy four RA patients (ACR 1987) with EAM, > 18 years, more than 6 months duration were included, and an EAM free control, matched by sex and age, for each patient. Demographic, clinical and laboratory variables were compared using t-test, chi-square or Mann-Whitney test. Multivariate analysis was performed: p ≤ 0.05. Patients with EAM presented a greater value of ACCP antibody (116 vs. 34, p < 0.01) and rheumatoid factor (108 vs. 34.5, p < 0.01). Independent association with current smoking habit (p = 0.02, OR = 3.78, 95%: 1.17-12.2), RF positive (p = 0.04, OR 3.23, CI 95%: 1.04 to 11.8) and ACCP antibody positive (p = 0.04, OR 3.23, 95% CI: 1.04-10) was found. The patients with xerostomia (109 vs. 34, p = 0.04), xerophthalmia (150 vs. 34, p < 0.01), subcutaneous nodules (141 vs. 34, p < 0.01) and pulmonary fibrosis (158 vs. 34, p = 0.04) had a higher degree of the ACCP antibody, than controls. In conclusion, ACCP antibody positive, RF positive and smoking were independent risk factors for the development of MEXA.(AU)

Anticuerpo anticitrulina y manifestaciones extra articulares en artritis reumatoidea. / [Anticitrulin antibody and the extra-articular manifestations in rheumatoid arthritis].

A large proportion of rheumatoid arthritis (RA) patients develop extra-articular manifestations (EAM), which are associated with morbidity and early mortality. Anti cyclic citrullinated peptide (ACCP) antibody has proven to be highly specific for the diagnosis of RA, associated with severe joint damage and may have some role in the pathogenesis of EAM. The aim of this study was to determine the relationship between ACCP antibody and the presence of EAM in RA patients. Seventy four RA patients (ACR 1987) with EAM, > 18 years, more than 6 months duration were included, and an EAM free control, matched by sex and age, for each patient. Demographic, clinical and laboratory variables were compared using t-test, chi-square or Mann-Whitney test. Multivariate analysis was performed: p = 0.05. Patients with EAM presented a greater value of ACCP antibody (116 vs. 34, p < 0.01) and rheumatoid factor (108 vs. 34.5, p < 0.01). Independent association with current smoking habit (p = 0.02, OR = 3.78, 95

: 1.17-12.2), RF positive (p = 0.04, OR 3.23, CI 95

: 1.04 to 11.8) and ACCP antibody positive (p = 0.04, OR 3.23, 95

CI: 1.04-10) was found. The patients with xerostomia (109 vs. 34, p = 0.04), xerophthalmia (150 vs. 34, p < 0.01), subcutaneous nodules (141 vs. 34, p < 0.01) and pulmonary fibrosis (158 vs. 34, p = 0.04) had a higher degree of the ACCP antibody, than controls. In conclusion, ACCP antibody positive, RF positive and smoking were independent risk factors for the development of MEXA.

Autoanticorpos na artrite reumatoide inicial: coorte Brasília - resultados de uma análise seriada de três anos / Autoantibodies in early rheumatoid arthritis: Brasília cohort - results of a three-year serial analysis

O valor diagnóstico e prognóstico da análise seriada dos anticorpos como fator reumatoide (FR), anticorpos antipeptídeos citrulinados cíclicos (anti-CCP) e antivimentina citrulinada (anti-Sa) não está definido nos pacientes com artrite reumatoide inicial (ERA). OBJETIVOS: Avaliar de forma prospectiva a presença de FR, anti-CCP e anti-Sa em pacientes com ERA. PACIENTES E MÉTODOS: Quarenta pacientes da coorte Brasília de ERA (menos de 12 meses) foram avaliados e monitorados durante três anos. Os dados clínicos e demográficos foram registrados, além dos resultados (ELISA) para FR (IgM, IgG e IgA), anti-CCP (CCP2, CCP3 e CCP3.1) e anti-Sa na avaliação inicial e aos 3, 6, 12, 18, 24 e 36 meses de acompanhamento. Comparações pelos testes t de Student e t pareado. RESULTADOS: A idade média foi de 45 anos, 90% dos pacientes do gênero feminino. No momento do diagnóstico, FR foi observado em 50% dos casos (FR IgA 42%, FR IgG 30% e FR IgM 50%), anti-CCP em 52,5% (não houve diferença entre CCP2, CCP3 e CCP3.1) e anti-Sa em 10%. Após três anos, não houve diferença na prevalência de FR e anti-CCP, mas a de anti-Sa aumentou para 17,5% (P = 0,001). CONCLUSÃO: A análise repetida do FR e anti-CCP, incluindo aqui diferentes isotipos, durante três anos de acompanhamento, não mostrou mudanças significativas. A terceira geração do anti-CCP não aumentou o valor diagnóstico dos testes de segunda geração.

The diagnostic and prognostic value of the serial measurement of antibodies, such as rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and anti-citrullinated vimentin (anti-Sa) antibodies, has not been defined in early rheumatoid arthritis (ERA). OBJECTIVES: To prospectively assess the presence of RF, anti-CCP, and anti-Sa in ERA patients. PATIENTS AND METHODS: Forty ERA (less than 12 months) patients of the Brasília cohort were evaluated and followed up for three years. Both clinical and demographic data were recorded, in addition to the results (ELISA) of RF (IgM, IgG, and IgA), anti-CCP (CCP2, CCP3, and CCP3.1), and anti-Sa at the baseline assessment and after 3, 6, 12, 18, 24 and 36 months of follow-up. The results were compared by use of Student t test and paired t test. RESULTS: The patients' mean age was 45 years, and 90% of them were female. At the time of diagnosis, RF was identified in 50% of the patients (RF IgA, 42%; RF IgG, 30%; and RF IgM, 50%), anti-CCP in 52.5% (no difference between CCP2, CCP3, and CCP3.1), and anti-Sa in 10%. After three years, no difference was observed in RF and anti-CCP prevalence, but anti-Sa increased to 17.5% (P = 0.001). CONCLUSION: Repeated RF and anti-CCP measurement, including different isotypes, during three years of follow-up showed no significant changes. The third generation of anti-CCP assays did not increase the diagnostic value of the second-generation assays.

Anticuerpos anti-péptido citrulinado cíclico / Cyclic citrullinated peptide antibodies

The determination of anti-cyclic citrullinated peptide antibodies (anti-CCP) is an extremely useful laboratory test in the differential diagnosis of patients in which Rheumatoid Arthritis (RA) is suspected. Citrullination is an unspecific protein modification associated to inflammation. The production of antibodies directed against citrullinated antigens in the synovial membrane is, on the contrary, specific for RA, for which important associations between these and the pathogen of the disease have been described. This review focuses on the different characteristics that make this test routinely asked for in clinical practice: high specificity; high positive predictive value in undifferentiated arthritis; early manifestation, development prior to clinical disease, and its association with a more aggressive course of the disease.

Anticuerpos anti-péptido citrulinado cíclico en artritis reumatoide, artritis psoriática y otras enfermedades / Anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis and psoriatic arthritis

The anti-cyclic citrullinated peptide (Anti-CCP) antibodies are actually the markers of highly specific recognize for rheumatoid arthritis (RA). Its presence in RA has been associated with higher disease clinical activity characterize by greater loss of function and development of erosive illness with important radiological damage. Furthermore, its production is an early process in RA development and because that, their presence is predictive for disease development. But in spite of the fact its high specificity, in the last years they also has been detected in other arthropathies diseases like psoriatic arthritis (PsA). Even if the prevalence of Anti-CCP in PsA reach values greater than expected for a disease different of AR, doesn`t reach statistical value, but its presence in this illness, like in AR, could might considerer a marker of disease severity, with development of aggressive clinic characteristics, polyarticular predominance, erosion presence and associated with shared epitope allele. The existing information don´t allow defining if this patience will develop more aggressive illness or existing concomitance of two joint diseases. More detail studies are necessary to defined that.