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BACKGROUND: In Rheumatoid Arthritis (RA), pulmonary involvement is one of the most frequent extra-articular manifestations. Several studies have demonstrated an association between RA-related lung disease and the positivity of anti-cyclic citrullinated peptide (anti-CCP) antibodies. OBJECTIVE: Our aim is to describe the frequency of pulmonary involvement in the RA population and investigate the association between anti-CCP antibodies and diverse lung compartment involvement in RA patients. METHODS: An observational retrospective cross-sectional study was conducted, during which data were collected from the medical records of the patients with RA who had been tested for anti-CCP antibodies and had thoracic high resolution computerized tomography (HRCT) evaluation from January 2011 to March 2022. The univariate and multivariate analyses using logistic regression models was performed to calculate odds ratios (ORs) with 95% CIs. RESULTS: A total of 390 patients with RA were included, the mean age of patients was 58.99 ± 12.44 years, with a predominance of females (85.9%). Two hundred and fifty-two (64.6%) patients were positive for anti-CCP antibodies. The frequency of RA-related lung diseases was 14.4% (n=56). The different manifestations observed in the thoracic HRCT included Nodules (67.9%), Interstitial lung disease (ILD) (28.6%), bronchiectasis (25%), fibrosis (21.4%), obliterative bronchiolitis (7.1%), and pleuritis (1.8%). In univariate and multivariate analysis, pulmonary involvement was associated with positive anti-CCP antibodies with an odds ratio (OR) of 5.25 (95% CI: 2.17-12.70, p < 0.0001). CONCLUSION: The study demonstrated a positive association between anti-CCP antibodies and pulmonary involvement in RA and highlighted the importance of tight monitoring in RA patients with positive anti-CCP for pulmonary complications.

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Background: Anti-citrullinated protein antibodies (ACPA) are a specific serological biomarker used in the diagnosis of rheumatoid arthritis (RA). In clinical practice ACPA can be identified using immunoassays targeting synthetic cyclic citrullinated peptides (CCP). The 3rd generation anti-CCP IgG antibody (CCP3) offers improved sensitivity compared to the earlier versions. Recently, CCP3.1, capable of detecting both IgG and IgA antibodies, was introduced to enhance sensitivity, especially in patients with early RA. Methods: We assessed serum CCP3.1 against CCP3 in 331 subjects undergoing RA panel serology, comprising 136 patients with RA and 195 patients without RA. Sera were tested for anti-CCP IgG (CCP3) and anti-CCP IgG/IgA (CCP3.1) antibodies. Clinical performance of these tests was compared at manufacturer-suggested cutoffs. A separate set of 81 patients with a diagnosis of RA by 2010 criteria and whose samples were obtained from within 1-year of RA diagnosis was similarly assessed to evaluate assay performance in an independent clinical RA cohort. Results: Overall diagnostic accuracy was similar; CCP3 had an area under the curve (AUC) of 0.88, CCP3.1 had an AUC of 0.89. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CCP3 were 79 %, 91 %, 86 %, and 86 %, respectively. For CCP3.1, sensitivity was 78 %, specificity 93 %, PPV 89 %, NPV 86 %. Both assays demonstrated excellent agreement; positive percent agreement of 94 % and negative percent agreement of 99 %. Conclusion: Our findings indicate comparable diagnostic accuracy between CCP3 and CCP3.1 assays in these clinical cohorts.

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Characterization of peptide antibodies through identification of their target epitopes is of utmost importance, as information about epitopes provide important knowledge, among others, for discovery and development of new therapeutics, vaccines, and diagnostics.This chapter describes a strategy for mapping of continuous peptide antibody epitopes using resin-bound and soluble peptides. The approach combines three different types of peptide sets for full characterization of peptide antibodies; (i) overlapping peptides, used to locate antigenic regions; (ii) truncated peptides, used to identify the minimal peptide length required for antibody binding; and (iii) substituted peptides, used to identify the key residues important for antibody binding and to determine the specific contribution of key residues. For initial screening, resin-bound peptides are used for epitope estimation, while soluble peptides subsequently are used for final epitope characterization and identification of critical hot spot residues. The combination of resin-bound peptides and soluble peptides for epitope mapping provides a time-saving and straightforward approach for characterization of antibodies recognizing continuous epitopes, which applies to peptide antibodies and occasionally antibodies directed to larger proteins as well.

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Immunoblotting, also termed western blotting, is a powerful method for detection and characterization of proteins separated by various electrophoretic techniques. The combination of sodium dodecyl sulfate-poly acrylamide gel electrophoresis (SDS-PAGE), having high separating power, immunoblotting to synthetic membranes, and detection with highly specific peptide antibodies, is especially useful for studying individual proteins in relation to cellular processes, disease mechanisms, etc. Here, we describe a protocol for the sequential detection of various forms of an individual protein using peptide antibodies, exemplified by the characterization of antibody specificity for different forms of the protein calreticulin by double SDS-PAGE immunoblotting.

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Peptide antibodies are particularly useful for immunocytochemistry (ICC) and immunohistochemistry (IHC), where antigens may denature due to fixation of tissues and cells. Peptide antibodies can be made to any defined sequence, including unknown putative proteins and posttranslationally modified sequences. Moreover, the availability of large amounts of the antigen (peptide) allows inhibition/absorption controls, which are important in ICC/IHC, due to the many possibilities for false-positive reactions caused by immunoglobulin Fc receptors, nonspecific reactions and cross-reactivity of primary and secondary antibodies with other antigens and endogenous immunoglobulins, respectively. Here, simple protocols for ICC and IHC are described together with recommendations for appropriate controls.

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Rheumatoid meningitis (RM) is a rare but serious extra-articular manifestation of rheumatoid arthritis. Due to the absence of specific biomarkers, imaging findings, or guidelines for its detection, the diagnosis of RM is difficult. This report describes a patient of RM diagnosed with an open biopsy and discusses the utility of anticyclic citrullinated peptide antibodies (ACPA) levels in the serum and cerebrospinal fluid (CSF), and contrast-enhanced (CE) fluid-attenuated inversion recovery (FLAIR) images for screening and monitoring RM. A 65-year-old woman presented with a 2-month history of headaches. Imaging studies showed asymmetric meningeal and leptomeningeal involvement seen on brain magnetic resonance imaging (MRI). An open biopsy of the meninges and leptomeninges depicted palisaded and necrotizing granulomatous inflammation, which suggests rheumatoid nodules. Treatment with prednisolone and tocilizumab led to symptom improvement and reduced lesion intensity on follow-up MRI. Throughout the treatment, the ACPA index in her serum and CSF, and the findings of CE-FLAIR images, rather than the CE T1WI, reflected disease activity. For 6 months, the patient has been stable without symptom recurrence. The ACPA index and the CE-FLAIR images were useful for the diagnosis and monitoring of RM. To validate these findings, further studies are necessary.

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INTRODUCTION: Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood, affecting one to four of every 1000 children worldwide. It is characterized by joint inflammation lasting more than six weeks in children under 16 years. The aim of this study was to estimate the frequency of JIA subtypes in the Mexican patient population; compare clinical, immunological and inflammation markers by JIA subtype; and examine the correlation between these variables. METHODS: We conducted a cross-sectional study of 50 patients with JIA (2-15 years). We estimated the frequency of each JIA subtype, assessed and compared the immunological characteristics (RF, ANA and anti-CCP) by JIA subtype at the time of diagnosis using Kruskal-Wallis or chi-square tests, and calculated Spearman correlation coefficients between the assessments. RESULTS: Our analysis included 50 patients, 29 (58%) girls and 21 (42%) boys, aged at the time of diagnosis 10.56 ± 3.99 years. The frequencies of JIA subtypes were RF-seropositive polyarthritis (34%), RF-seronegative polyarthritis (28%), systemic arthritis (16%), oligoarthritis (14%) and arthritis-related enthesitis (8%). We found a significant association between sex and JIA subtype (p = 0.014). There was a significant difference in anti-CCP levels by JIA subtype (p < 0.001). We also detected positive correlations between RF and anti-CCP (r = 0.63, p < 0.001) and between age and anti-CCP (r = 0.29, p = 0.041). CONCLUSIONS: Our study suggests that the frequency of the polyarticular subtypes of JIA is higher in Mexican children compared to other populations. Our findings highlight the importance of considering the presence of anti-CCP and RF as important criteria when deciding on treatment for JIA patients as elevated levels of these antibodies may indicate early forms of adult rheumatoid arthritis.

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OBJECTIVE:At present,there are many reports on the related factors associated with the incidence of cervical spine instability in patients with rheumatoid arthritis,but there are problems such as small sample size and many confounding factors,and the research results of various studies on the same related factors are also different.This article analyzed the factors related to cervical spine instability in patients with rheumatoid arthritis by means of a systematic review. METHODS:Articles related to cervical spine instability in patients with rheumatoid arthritis were collected by searching both Chinese and English databases until March 2023.The outcome of cervical spine instability in patients with rheumatoid arthritis was used as the grouping criterion to abstract basic information,baseline patient characteristics,laboratory-related tests,medication use,and other relevant risk factors.Meta-analysis was done using Stata 14.0 software. RESULTS:(1)Sixteen relevant studies,all of moderate or above quality,were included,including seven studies with case-control studies and nine with cross-sectional studies.The overall incidence of cervical spine instability in patients with rheumatoid arthritis was 43.08%.(2)Meta-analysis showed:Related risk factors included female(OR=0.60,95%CI:0.44-0.82,P=0.002);age at disease onset(SMD=-0.52,95%CI:-0.86 to-0.18,P=0.003);duration of disease(SMD=0.58,95%CI:0.14-1.02,P=0.01);body mass index(OR=0.74,95%CI:0.63-0.88,P=0.001);rheumatoid factors positive univariate analysis subgroup(OR=1.33,95%CI:1.02 to 1.72,P=0.04),C-reactive protein(SMD=0.26,95%CI:0.16-0.35,P=0.00),erythrocyte sedimentation rate(SMD=0.15,95%CI:0.002-0.29,P=0.047),anti-cyclic-citrullinated peptide antibodies(OR=1.73,95%CI:1.19-2.51,P=0.004),28-joint Disease Activity Score(SMD=0.20,95%CI:0.04-0.37,P=0.02),destruction of peripheral joints(OR=2.48,95%CI:1.60-3.85,P=0.00),and corticosteroids(OR=1.91,95%CI:1.54-2.37,P=0.00)were strongly associated with the development of rheumatoid arthritis-cervical spine instability.Female and corticosteroid use were independently associated with the occurrence of rheumatoid arthritis-cervical spine instability. CONCLUSION:Based on clinical evidence from 16 observational studies,the overall incidence of rheumatoid arthritis-cervical spine instability was 43.08%.However,the incidence of cervical spine instability in rheumatoid arthritis patients varied greatly among different studies.Gender(female)and the use of corticosteroids were confirmed as independent correlation factors for the onset of cervical spine instability in patients with rheumatoid arthritis.The results of this study still provide some guidance for early clinical recognition,diagnosis,and prevention of rheumatoid arthritis-cervical spine instability.

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OBJECTIVES: The aim of the present study was to evaluate performance of serum and synovial fluid levels of the granulocyte protein calprotectin as inflammatory biomarker in rheumatoid arthritis (RA) patients with knee synovitis. METHODS: 76 RA patients with ongoing knee synovitis were included. Data on disease activity score with 28 joints and their subcomponents and radiological destruction of the affected knee were collected. White blood cell count, C-reactive protein, anti-citrullinated peptide antibodies (ACPA) against cyclic citrullinated peptide version 2 (anti-CCP2), IgM rheumatoid factor (RF) and calprotectin were analysed in parallel in circulation and in synovial fluid (SF). Counts of polynuclear and mononuclear cells were measured in SF. RESULTS: Serum (S) calprotectin correlated stronger than SF-calprotectin with inflammatory markers and disease activity. Instead, SF-calprotectin showed a strong correlation to SF counts of white blood cells, and especially to polymorphonuclear cell counts (Spearman's rho = 0.72, p< 0.001). S-calprotectin showed markedly stronger correlation with inflammatory markers and disease activity in ACPA positive as compared with ACPA negative RA patients; a similar difference was observed for patients with and without IgM RF. CONCLUSION: The particularly strong association between circulating calprotectin and inflammation in ACPA positive RA is a new argument for a specific role for polymorphonuclear granulocytes/neutrophils in this RA subset. Measurement of calprotectin in SF does not convey any additional benefit compared with measurement in the circulation in RA patients with knee synovitis.

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Introduction The most prevalent chronic human autoimmune disorder worldwide is rheumatoid arthritis. Synovial samples from acute-phase patients are polymerase chain reaction-positive for Chlamydia pneumoniae (C. pneumoniae) DNA and express chlamydial hsp60. Furthermore, anti-cyclic citrullinated peptide (anti-CCP) antibodies promote apoptosis of mature human Saos-2 osteoblasts via cell surface binding to citrullinated heat shock protein 60 (HSP60). Hence, we hypothesised that C. pneumoniae infection is associated with anti-CCP antibodies. Methods C. pneumoniae IgA and anti-CCP antibody levels were determined in 26 healthy subjects in this cross-sectional study. Serum C. pneumoniae IgA antibody levels were assessed using an enzyme-linked immunosorbent assay. Serum anti-CCP antibody levels were assessed using fluoroenzymeimmunoassay. Results There was a highly significant positive correlation between the two sets of antibodies (rs = 0.621; P = 0.0007). Linear regression analysis showed that this correlation was not the result of age or sex. Discussion A biologically plausible mechanism is put forward for these results, involving HSP60 acting as an endogenous ligand for toll-like receptor 4 (TLR4) and the interaction of TLR4 with lipopolysaccharides, which occur in the outer membrane of the C. pneumoniae elementary body. Pronounced pro-inflammatory mediator secretion then takes place. The release of Ca2+ ions may then activate local peptidylarginine deiminases, leading to the formation of CCPs and thus the reported finding. Confirmation of these results may have potential clinical implications in terms of diagnosis, including pre-symptomatic diagnosis, and treatment.

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The constant evolution of pathogenic viral variants and the emergence of new viruses have reinforced the need for broad-spectrum vaccines to combat such threats. The spread of new viral variants leading to epidemic and pandemic infection can be effectively contained, if broad-spectrum vaccines effective against the newer viral variants are readily available. The development of broad-spectrum, pan-neutralising antibodies against viruses which, in general terms, are very antigenically different - such as HIV, influenza virus and paramyxoviruses - has been reported in the literature. The amino acid sequences used to generate a range of approved recombinant anti-viral vaccines were analysed by using in silico methods, with the aim of identifying highly antigenic peptide regions that may be suitable for the development of broad-spectrum peptide-based anti-viral vaccines. This was achieved through the use of open-source data, an algorithm-driven probability matrix, and published in silico prediction tools (SVMTriP, IEDB-AR, VaxiJen 2.0, AllergenFP v. 1.0, AllerTOP v. 2.0, ToxinPred and ProtParam) to evaluate antigenicity, MHC-I and MHC-II binding potential, immunogenicity, allergenicity, toxicity and physicochemical properties. We report a pan-antigenic peptide region with strong affinity for MHC-I and MHC-II, and good immunogenic potential. According to the output from the relevant in silico tools, the peptide was predicted to be non-toxic, non-allergic and to possess the desired physicochemical properties for potentially successful vaccine production. With further investigation and optimisation, this peptide could be considered for use in the development of a broad-spectrum anti-viral vaccine that may protect against emerging new viruses. Our approach of using in silico methods to identify candidate antigenic peptides with the desired physicochemical properties could potentially circumvent the use of some animal studies for peptide vaccine candidate evaluation.

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Rheumatoid arthritis (RA), a chronic inflammatory disease, carries a significant burden of atherosclerotic cardiovascular diseases (ASCVD). With their heterogeneous composition, high-density lipoprotein (HDL) particles have varied athero-protective properties, and some may even increase ASCVD risk. In this prospective and cross-sectional study, we aimed to examine the relationship between HDL sizes/metabolites and inflammation in RA. Using 1H-NMR-based lipid/metabolomics, differential HDL-related metabolites were identified between RA patients and healthy control (HC) subjects and between RA patients with and without anti-citrullinated peptide antibodies (ACPA). The correlation between the discriminative HDL-related metabolites and C-reactive protein (CRP) was evaluated in RA patients. RA patients demonstrated higher particle number, lipids, cholesterol, cholesterol ester, free cholesterol, and phospholipids in large/very large-sized HDLs. ACPA-positive patients had higher L-HDL-C and L-HDL-CE but lower small-/medium-sized HDL-TG levels than ACPA-negative patients. An inverse correlation was found between CRP levels and small-sized HDLs. Janus kinase inhibitor treatment was associated with increased serum small-sized HDL-related metabolites and decreased CRP levels. We are the first to reveal the significant associations between RA inflammation and HDL sizes/metabolites. A potential link between ACPA positivity and changes in serum levels of HDL-related metabolites was also observed in RA patients.

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BACKGROUND: Primary biliary cholangitis (PBC) is an autoimmune disease of the liver characterized by destructive lymphocytic cholangitis and anti-mitochondrial antibodies (AMA). Anti-gp210 and anti-Sp100, are used for the diagnosis of PBC in AMA-negative PBC patients. Patients with PBC have a propensity to have an extrahepatic manifestation which is especially autoimmune. OBJECTIVE: We aimed to determine the frequency of serological markers of rheumatoid arthritis (RA) (CCP-Ab or RF) in PBC patients and to do the vice versa. METHODS: Our PBC study included 70 patients with PBC and 80 healthy blood donors (HBD) and our RA study included 75 patients with RA and 75 HBD. Anti-cyclic citrullinated peptide antibodies (CCP-Ab) and rheumatoid factor (RF) were performed by indirect ELISA. AMA, anti-Sp100 and anti-gp210 were determined by indirect immunofluorescence. RESULTS: RA autoantibodies (CCP-Ab or RF) were more frequent in PBC patients than in HBD (65.7% vs. 8.7% p ã€ˆ10-6). CCP-Ab were significantly more frequent in patients than in controls (15.7% vs. 2.5%; p = 0.004). Nine patients had both CCP-Ab and RF vs. none of controls (12.8% vs. 0%; p = 0.001). RF were detected in 45 patients with PBC and in 5 HBD (64.3% vs. 6.2%; p ã€ˆ10-6). In PBC patients, RF were more frequent than CCP-Ab (64.3% vs. 15.7%; p ã€ˆ10-6). RF-IgG were present in 18.5% of patients; RF-immunoglobulin (Ig) A in 34.3% and RF-IgM in 54.3%. These frequencies were significantly higher than those found in control group (1.2% for RF-IgG (p ã€ˆ10-3); 0% for RF-IgA (p ã€ˆ10-6); and 6.2% for RF-IgM (p ã€ˆ10-6)). In our PBC patients, RF-IgA were more frequent than RF-IgG (34.3% vs. 18.5%; p = 0.03) and than CCP-Ab (34.3% vs. 15.7%; p = 0.01). Six patients had only RF-IgA versus none of the control group (8.6% vs. 0%; p = 0.01). AMA, anti-Sp100 and anti-gp 210 were absent in all RA patients. CONCLUSIONS: Serological markers of RA were more frequent in PBC patients than in HBD and the vice versa was not true.

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Introduction: The most important genetic association in rheumatoid arthritis (RA) is presented with some alleles from the HLA-DRB1 gene that encode the shared epitope (SE). Objectives: To apply the SE classification methods of Gregersen, de Vries, Raychaudhuri, Mattey, and Tezenas du Montcel in a group of Colombian patients with RA and determine the most common HLA-DRB1 alleles in the population. Methods: RA diagnosis, genetic study of the HLA-DRB1 region using Luminex technology in 50 RA and 50 healthy subjects. For the classification analysis, Fisher's exact test and chi-squared test were applied. Tables were created to count the RA-related alleles. We used odds ratio to determine the risk between the presence of the shared epitope (SE) and anti-cyclic citrullinated peptides (Anti-CCP). Results: Gregersen and de Vries methods were suitable for the characterization of RA in this population (p = .006). The most prevalent HLA-DRB1 alleles in the RA group were 14:02,04:04, 08:02,04:05, and 10:01. High frequencies of the 07:01, 03:01,13:02,01:02, and 12:01 HLA-DRB1 alleles were found in the healthy population. HLA-DRB1 alleles with similar distribution in both populations were 04:07, 15:01, 11:01, 16:02, and 01:01. A high frequency of SE + was observed in Anti-CCP + individuals (63.15%); however, this was not statistically significant [OR2.4 (.63-9.01); p = .19]. Conclusion: The SE classification methods of Gregersen and de Vries were adequate in characterizing RA in a Colombian population group. An equivalence of 100% was verified between the susceptibility alleles defined by de Vries and the alleles assigned as SE according to Gregersen.

Introducción: La asociación genética más importante en artritis reumatoide (AR) se presenta con algunos alelos del gen HLA DRB1 que codifican el epítope compartido (EC). Objetivos: Aplicar los métodos de clasificación de EC de Gregersen et al., de Vries et al., Raychaudhuri et al., Mattey et al., y Tezenas du Montcel et al., en un grupo de pacientes colombianos con AR, y determinar los alelos HLA DRB1 más frecuentes en esta población. Métodos: Diagnóstico para AR, estudio genético de la región HLA DRB1 por tecnología Luminex® de 50 sujetos AR y 50 sanos. Para análisis comparativos de clasificaciones EC, se aplicaron las pruebas test exacto de Fisher y Chi-cuadrado y se realizaron tablas de conteos para los alelos relacionados con AR. Se estimó la razón de odds para determinar el riesgo entre la presencia de EC y los anticuerpos antipéptidos cíclicos citrulinados (anti-PCC). Resultados: Los métodos de Gregersen et al. y de Vries et al. fueron adecuados para la caracterización de AR en esta población (p = 0,006). Los alelos HLA DRB1 más prevalentes en el grupo AR fueron 14:02, 04:04, 08:02, 04:05 y 10:01. Se encontraron altas frecuencias de los alelos HLA DRB1 07:01, 03:01,13:02, 01:02 y 12:01 en población sana. Alelos HLA DRB1 con distribución similar en ambas poblaciones fueron: 04:07, 15:01, 11:01, 16:02 y 01:01. Se observó alta frecuencia de individuos EC+ en el grupo AR anti-PCC+ (63,15%); no obstante, sin asociación estadística (OR: 2,4 [0,63-9,01]; p = 0,19). Conclusión: Los métodos de clasificación para EC de Gregersen et al. y de Vries et al. fueron adecuados caracterizando AR en un grupo de población colombiana. Se corroboró equivalencia del 100% entre los alelos de susceptibilidad definidos por de Vries y los alelos asignados como EC según Gregersen et al.

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Objective: To identify differential features between patients with seropositive and seronegative rheumatoid arthritis (RA). Method: Prospective cohort study, including patients who were admitted for polyarthralgia. At baseline was performed: laboratory studies, X-rays of hands and feet, ultrasound of both hands with power Doppler technique, clinical data and clinimetry. In subsequent visits the definitive diagnosis of RA was established or not. It was considered as seronegative RA when patients were negative for both RF and ACPAs. Results: 746 patients were included, of which 128 (17.1%) ended with a final diagnosis of RA. Of these 128 patients, 87 (67.9%) were seropositive RA, while 41 (32%) were seronegative RA. The only feature that showed significant differences was the presence of tenosynovitis detected by ultrasound with a positive power Doppler signal, 13.7% of the patients with seropositive RA vs 41.6% of the patients with seronegative RA (p=0.0028). Conclusion: The only differential feature of patients with seronegative RA was the higher proportion of tenosynovitis detected by ultrasound.(AU)

Objetivo: Identificar características diferenciales entre pacientes con artritis reumatoide (AR) seropositivos y seronegativos. Método: Estudio de cohorte prospectivo, incluyendo pacientes con poliartralgias. Al inicio se realizó: estudios de laboratorio, radiografías de manos y pies, ecografía de ambas manos con técnica power doppler, datos clínicos y clinimetría. En visitas posteriores se estableció o no el diagnóstico definitivo de AR. Se consideró AR seronegativa cuando los pacientes eran negativos tanto para factor reumatoide como para anticuerpos antipéptido cíclico citrulinado. Resultados: Se incluyeron 746 pacientes, de los cuales 128 (17,1%) terminaron con diagnóstico final de AR. De estos 128 pacientes, 87 (67,9%) eran AR seropositivos, mientras que 41 (32%) eran AR seronegativos.La única característica que mostró diferencias significativas fue la presencia de tenosinovitis detectada por ecografía con señal power doppler positiva, el 13,7% de los pacientes con AR seropositiva frente al 41,6% de los pacientes con AR seronegativa (p=0,0028). Conclusión: El único rasgo diferencial de los pacientes con AR seronegativa fue la mayor proporción de tenosinovitis detectadas por ecografía.(AU)

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OBJECTIVE: To identify differential features between patients with seropositive and seronegative rheumatoid arthritis (RA). METHOD: Prospective cohort study, including patients who were admitted for polyarthralgia. At baseline was performed: laboratory studies, X-rays of hands and feet, ultrasound of both hands with power Doppler technique, clinical data and clinimetry. In subsequent visits the definitive diagnosis of RA was established or not. It was considered as seronegative RA when patients were negative for both RF and ACPAs. RESULTS: 746 patients were included, of which 128 (17.1%) ended with a final diagnosis of RA. Of these 128 patients, 87 (67.9%) were seropositive RA, while 41 (32%) were seronegative RA. The only feature that showed significant differences was the presence of tenosynovitis detected by ultrasound with a positive power Doppler signal, 13.7% of the patients with seropositive RA vs 41.6% of the patients with seronegative RA (p=0.0028). CONCLUSION: The only differential feature of patients with seronegative RA was the higher proportion of tenosynovitis detected by ultrasound.

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Introduction: To explore the value of serum sirtuin-1 (SIRT1) in the diagnosis and evaluation of joint mobility of rheumatoid arthritis (RA). Materials and Methods: Serum was randomly obtained from 212 RA patients,210 non-RA patients and 58 healthy controls in a large tertiary first-class hospital in Jiangxi province from November 2021 to June 2022. The level of serum Sirt1,anti-cyclic citrulline polypeptide antibody (anti-CCP), anti-mutant citrulline vimentin antibody (anti-MCV), rheumatoid factor (RF),high-mobility group box 1 (HMGB1), collagen triple helix repeat containing 1 (CTHRC1), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were detected by ELISA, to explore the correlation between them and their value in the diagnosis and evaluation of joint range of motion of RA and statistically analyse their diagnostic efficiency. Results: ① The level of all markers was higher in the RA group than in the non-RA group and the healthy controls (p < 0.05). ② The AUC of the SIRT1 was 0.882, second only to the anti-MCV and anti-CCP. ③ The anti-CCP showed the highest sensitivity to RA diagnosis of 0.948. The specificity and positive predictive value of SIRT1 for the diagnosis of RA were the highest, which are 0.959 and 0.934 respectively. ④ In serial combination, SIRT1/anti-CCP、SIRT1/anti-MCV showed the highest specificity.SIRT1/anti-CCP in parallel combination had the highest sensitivity. ⑤ SIRT1 showed a significant correlation with other markers and DAS28 scores (p < 0.01). Conclusion: SIRT1 can be used as a new serological marker for RA diagnosis, which has a significant correlation with RA joint mobility and has a certain reference value in RA differential diagnosis, providing a new detection basis for RA differential diagnosis.

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Rheumatoid meningitis (RM) is a rare complication of rheumatoid arthritis that can manifest as stroke-like episodes. We present the case of a 63-year-old woman with a past history of overlap syndrome and clinical manifestations suggestive of amyopathic dermatomyositis, rheumatoid arthritis, and systemic lupus erythematosus. She presented to the emergency department with sudden onset right-sided clumsiness and numbness, as well as a 2-week history of left hemicranial headache. Laboratory workup revealed positive serum antinuclear antibodies, anti-Ro antibodies, anti-citrullinated peptide antibodies (ACPA), and elevated rheumatoid factor. Lymphocytic pleocytosis, positive ACPA and anti-Ro antibodies with passive diffusion pattern, and negative microbiological studies were demonstrated in the CSF. Brain magnetic resonance imaging showed predominant left fronto-parieto-occipital leptomeningeal and pachimeningeal enhancement. She was diagnosed with RM and received methylprednisolone IV mg/kg once daily. Stroke-like episodes in the setting of a patient with lymphocytic pleocytosis in the cerebrospinal fluid (CSF) and meningeal enhancement should raise suspicion of RM. In this context, serum rheumatoid factor and ACPA levels should always be measured and ACPA should also be measured in CSF. To our knowledge, this is the first reported case of RM in the context of an overlap syndrome. ACPA levels in CSF could be a relevant diagnostic clue in the setting of central nervous system disturbance and overlapping autoimmune conditions that include rheumatoid arthritis. In our case, the presence of a suggestive clinical scenario of RM reinforces the probable pathogenic role of ACPA when it is present in the central nervous system, even without intrathecal synthesis evidence.

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Molecularly imprinted polymers (MIPs) are chemical antibody mimics obtained by nanomoulding the 3D shape and chemical functionalities of a desired target in a synthetic polymer. Consequently, they possess exquisite molecular recognition cavities for binding the target molecule, often with specificity and affinity similar to those of antigen-antibody interactions. Research on MIPs targeting proteins began in the mid-90s, and this review will evaluate the progress made till now, starting from their synthesis in a monolith bulk format through surface imprinting to biocompatible soluble nanogels prepared by solid-phase synthesis. MIPs in the latter format will be discussed more in detail because of their tremendous potential of replacing antibodies in the biomedical domain like in diagnostics and therapeutics, where the workforce of antibodies is concentrated. Emphasis is also put on the development of epitope imprinting, which consists of imprinting a short surface-exposed fragment of a protein, resulting in MIPs capable of selectively recognizing the whole macromolecule, amidst others in complex biological media, on cells or tissues. Thus selecting the 'best' peptide antigen is crucial and in this context a rational approach, inspired from that used to predict peptide immunogens for peptide antibodies, is described for its unambiguous identification.

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OBJECTIVES: Polyarticular juvenile idiopathic arthritis (pJIA) is a subset of juvenile idiopathic arthritis (JIA), divided into two subtypes according to the presence of rheumatoid factor: pJIA without rheumatoid factor (pJIA RF-) and pJIA with positive rheumatoid factor (pJIA RF+), this latter is characterised with more structural damage. Anti-citrullinated peptide antibodies (ACPA) are often associated with RF. The respective performance of ACPA versus RF in structural outcome in pJIA, and in particular in adulthood pJIA remains unknown. Therefore, the aim of this study was to determine whether ACPA could be of value to assess structural damage in pJIA persisting in adulthood. METHODS: Patients with pJIA and available data for ACPA, RF and X-ray were included retrospectively. Structural damage was assessed by two independent blinded investigators using Sharp Van Der Heijde scores. RESULTS: 56 pJIA adult patients were included: 62% (35/56) had pJIA RF+ and 38% (21/56) pJIA RF-. ACPA positivity in pJIA was significantly associated with presence of RF (96% vs 26%, P<0.001). RF positivity was significantly associated with higher Sharp van Der Heijde erosion and total scores (respectively P<0.01 and P<0.05). There were higher Sharp Van Der Heijde erosion, joint space narrowing and total scores in the pJIA ACPA+ subgroup than in the pJIA ACPA- subgroup, although there was no statistical significance. However, when adjusted on disease duration, pJIA ACPA+ patients had significantly higher erosion and total scores than pJIA ACPA- patients (P<0.05), and pJIA ACPA+ patients required more bDMARDs than pJIA ACPA- patients (P<0.05). Moreover, pJIA patients with high Sharp van Der Heijde joint space narrowing and total scores had significantly higher ACPA levels (P<0.01). A correlation was identified between ACPA levels and Sharp van Der Heijde total score (r=0.54, P<0.05). In the pJIA RF+ subgroup the presence of ACPA was associated with additional structural damage compared to no ACPA: sharp Van Der Heijde erosion, joint space narrowing and total scores were higher in the pJIA RF+ ACPA+ subgroup than in the pJIA RF+ ACPA- subgroup although these results did not reach significance. CONCLUSION: Our results suggest that pJIA RF+ ACPA+ adult patients may have a more severe articular phenotype than pJIA RF+ ACPA- patients. ACPA could bring an additional value to RF for pJIA patients regarding structural damage. Altogether our results show that RF and ACPA are associated with structural damage measured by Sharp Van Der Heijde score in pJIA persisting in adulthood.

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