Presence of Autoantibodies in Males and Females With Rheumatoid Arthritis: A Systematic Review and Metaanalysis

Rheumatoid Factor: Diagnostic and Prognostic Performance and Therapeutic Implications in Rheumatoid Arthritis

Rheumatoid factor (RF) is the first autoantibody identified in rheumatoid arthritis (RA) which targets the fragment crystallizable (Fc) region of immunoglobulin (Ig) G. Although IgM isotype is predominant, other Ig isotypes, including IgG and IgA, also exist. While RF is not specific to RA, it remains a valuable serological test for diagnosing the disease, as evidenced by its inclusion in the 2010 classification criteria for RA based on elevated serum RF levels. RF is also associated with RA severity, including joint damage and extra-articular manifestations, serving as a poor prognostic factor and aiding in the identification of difficult-to-treat RA. Recent studies have demonstrated that high serum RF levels are associated with a reduced response to tumor necrosis factor (TNF) inhibitors. In contrast, anti-TNF antibodies lacking the Fc portion have shown stable efficacy in RA patients regardless of baseline RF levels. These findings reaffirm the clinical significance of RF measurement, 80 years after its initial discovery. This review explores the diagnostic and prognostic significance of RF and its impact on treatment selection in RA management.

Immunological landscape of periodontitis and rheumatoid arthritis and their molecular crosstalk

BACKGROUND

The association between periodontitis (PT) and rheumatoid arthritis (RA) is well-established; however, the molecular mechanisms underlying this relationship remain poorly understood. This study aims to delineate shared genetic and molecular features between PT and RA to uncover potential common pathways involved in their pathogenesis.

METHODS

Gene expression data sets for PT and RA were retrieved from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) and co-expressed gene modules were identified using weighted gene co-expression network analysis (WGCNA) and the DESeq2 package. Enrichment analyses, including KEGG and Gene Ontology (GO) pathways, as well as immune cell infiltration profiling, were performed to explore shared biological pathways. A protein-protein interaction (PPI) network was constructed to pinpoint key genes linking PT and RA. Functional assays were conducted by overexpressing the identified core gene, PTPRC, in MH7A cells via lentiviral transfection, followed by cell viability (CCK-8), migration, and invasion assays. In addition, transcription factor enrichment and connectivity map (cMAP) analyses were employed to identify common transcriptional regulators and potential therapeutic targets for both conditions.

RESULTS

WGCNA and DESeq2 analyses revealed 154 shared DEGs between PT and RA, predominantly enriched in immune and inflammatory response pathways. PTPRC emerged as a pivotal shared gene, exhibiting significantly higher expression in PT patients compared to controls. In vitro assays confirmed that PTPRC overexpression enhanced fibroblast proliferation, migration, and invasion. Furthermore, transcription factor enrichment analysis and cMAP identified overlapping transcriptional regulators and potential pharmacological agents for both diseases.

CONCLUSIONS

This study provides novel insights into shared gene expression profiles and molecular mechanisms linking PT and RA, identifying PTPRC as a potential key regulator. These findings suggest that targeting PTPRC could offer therapeutic opportunities for RA driven by PT.

Exploring Anticitrullinated Antibodies (ACPAs) and Serum-Derived Exosomes Cargoes

BACKGROUND

Autoantibodies such as rheumatoid factor (RF) and anticitrullinated protein autoantibodies (ACPAs) are useful tools for rheumatoid arthritis (RA). The presence of ACPAs against citrullinated proteins (CPs), especially citrullinated fibrinogen (cFBG), seems to be a useful serological marker for diagnosing RA. RA patients' sera were found to be enriched in exosomes that can transmit many proteins. Exosomes have been found to express citrullinated protein such as cFBG.

OBJECTIVE

We conducted this study in two stages. In the first phase, we aimed to evaluate the association between autoantibodies and risk factors. In the next step, ACPA-positive serum samples from the first phase were subjected to exosomal studies to explore the presence of cFBG, which is a frequent target for ACPAs.

METHODS

We investigated the autoantibodies in one hundred and sixteen Saudi RA patients and correlated with host-related risk factors. Exosomes were extracted from patients' sera and examined for the presence of cFBG using monoclonal antibodies.

RESULTS

The study reported a high female-to-male ratio of 8:1, and seropositive RA (SPRA) was more frequent among included RA patients. The frequency and the levels of ACPAs were similar in both genders. Autoantibodies incidences have a direct correlations with patient age, while the average titers decreased as the age increased. Further, the highest incidence and levels of autoantibodies were reported in patients with RA duration between 5 and 10 years. Smoking and family history have no impact on autoantibody, except for ACPAs titers among smokers' RA. Our analysis of serum exosomes revealed that about 50% of SPRA patients expressed cFBG.

CONCLUSIONS

The female-to-male ratio is 8:1, which is higher than the global ratio. We can conclude that patients' age and disease duration contribute to the autoantibodies, particularly RF and anti-MCV, whereas smoking and family history had no effects on autoantibodies. We detected cFBG in all exosomes from SPRA patients; thus, we suggest that the precise mechanism of exosomes in RA pathogenesis can be investigated to develop effective treatment strategies.

The first involved joints and associated factors in patients with rheumatoid arthritis

Objectives

This study aimed to investigate the first involved joints and associated factors in Turkish patients with rheumatoid arthritis (RA).

Patients and methods

This retrospective cross-sectional study included 300 newly diagnosed and disease-modifying antirheumatic drug-naïve RA patients (240 females, 60 males; mean age: 54±1.2 years; range, 18 to 82 years). Baseline demographic, clinical, and laboratory data were evaluated between January 2022 and December 2022. The patients were divided into four groups according to autoantibody profile: antibody-negative patients (Group 1; both RF and anti-CCP were negative in this group of patients), RF-positive patients (Group 2), anti-CCP-positive patients (Group 3), and patients with dual seropositivity with RF and antiCCP (Group 4). The patients were also divided into two groups according to the size of the first affected joint: patients with SJI at diagnosis and patients without SJI involvement at diagnosis.

Results

Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibody positivity rates were 40.3% and 35.6%, respectively. The mean lag time to diagnosis was 25±36 months. At the disease onset, 20% of patients did not have small joint involvement (SJI). Seronegative patients tended to be female (p=0.001), had longer lag time (p=0.001), and had lower levels of C-reactive protein (p=0.025), white blood count (p=0.005), and neutrophil/lymphocyte ratio (p=0.001) compared to the dual seropositive group. Patients presenting with SJI had a younger age (p=0.002), tended to be female (p=0.001), and had lower RF (p=0.034) and anti-CCP (p=0.031) positivity. Only age (p=0.005) and dual seronegativity (RF and anti-CCP; p=0.035) were the independent predictors of SJI in multivariate analysis.

Conclusion

The decreasing age and seronegative status were defined as independent risk factors of SJI at the onset of RA. Population-based, prospective studies are needed for earlier diagnosis.

Clinical Phenotypes, Serological Biomarkers, and Synovial Features Defining Seropositive and Seronegative Rheumatoid Arthritis: A Literature Review

Rheumatoid arthritis (RA) is a chronic autoimmune disorder which can lead to long-term joint damage and significantly reduced quality of life if not promptly diagnosed and adequately treated. Despite significant advances in treatment, about 40% of patients with RA do not respond to individual pharmacological agents and up to 20% do not respond to any of the available medications. To address this large unmet clinical need, several recent studies have focussed on an in-depth histological and molecular characterisation of the synovial tissue to drive the application of precision medicine to RA. Currently, RA patients are clinically divided into "seropositive" or "seronegative" RA, depending on the presence of routinely checked antibodies. Recent work has suggested that over the last two decades, long-term outcomes have improved significantly in seropositive RA but not in seronegative RA. Here, we present up-to-date differences in epidemiology, clinical features, and serological biomarkers in seronegative versus seropositive RA and discuss how histological and molecular synovial signatures, revealed by recent large synovial biopsy-based clinical trials, may be exploited to refine the classification of RA patients, especially in the seronegative group.

Impact of adverse drug reactions on the treatment pathways of early rheumatoid arthritis patients: a prospective observational cohort study

BACKGROUND

Several patient characteristics may be of influence on treatment pathways of rheumatoid arthritis (RA) patients in clinical practice. The aim of this study is to analyze treatment pathways of early RA patients stratified for gender and adverse drug reaction (ADR) occurrence.

RESEARCH DESIGN AND METHODS

Treatment pathways of patients included in the DREAM-RA treat-to-target cohort I between 16th of July 2006-30th of April 2020 were assessed. Treatment pathways were visualized in Sankey diagrams. Follow-up time, duration per treatment and the number of treatments received were stratified for gender and ADR occurrence and analyzed. Independent t-tests and chi-square tests were performed where applicable.

RESULTS

Treatment pathways of 372 patients (follow-up: 2488.4 years, mean 6.7 ± 3.7 years) were analyzed. The Sankey diagrams visualize that treatment pathways became increasingly varied and complex over time. No significant differences were found when comparing female patients and male patients. However, the average treatment duration was shorter in patients with ADRs (1.8 vs. 2.7 years, p < 0.05), and the number of treatments higher (3.5 vs. 2.5, p < 0.05).

CONCLUSIONS

Treatment pathways increase in complexity over time. Differences were found between patients with and without ADRs, with patients that experience ADRs receiving more and shorter treatments.