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Patients with established rheumatoid arthritis (RA) demonstrate altered immune responses to Epstein-Barr virus (EBV), but the presence and roles of EBV have not been fully explored during the pre-clinical disease period. This study was undertaken to determine if EBV infection, as evidenced by an altered anti-EBV antibody response, either plays an important role in driving the development of RA or is a result of expanded RA-related autoimmunity.A total of 83 subjects with RA according to the 1987 American College of Rheumatology (ACR) criteria and 83 age-, sex-, and race-matched control subjects without RA were included in our study. We collected sera from RA subjects and matched controls during the pre-RA and post-RA diagnosis periods and tested the sera for the presence of 5 anti-EBV antibodies (anti-EBV nuclear antigen 1 IgG isotype, anti-viral capsid antigen [anti-VCA] isotypes IgG and IgA, and anti-early antigen [EA] isotypes IgG and IgA), 7 RA-related autoantibodies (rheumatoid factor measured by nephelometry [RF-Neph] as well as isotype-specific IgA-RF, IgM-RF, and IgG-RF, and anti-cyclic citrullinated peptide [anti-CCP] antibodies, including anti-CCP2, anti-CCP3, and anti-CCP3.1), 22 cytokines/chemokines, 36 individual anti-citrullinated protein antibodies, and IgG-cytomegalovirus (CMV) antibodies. Random forest classification, mixed modeling, and joint mixed modeling were used to determine differences in anti-EBV antibody levels between RA subjects and controls.Random forest analysis identified the presence of preclinical EBV antibodies in the serum that differentiated RA subjects from controls without RA. Specifically, IgG-EA antibody levels were higher in RA subjects (mean ± SD 0.82 ± 0.72 international standardized ratio [ISR]) compared to controls (mean ± SD 0.49 ± 0.28 ISR). In subjects with RA, elevated serum IgG-EA levels in the preclinical period before seroconversion were significantly correlated with increased serum IgM-RF levels (P = 0.007), whereas this correlation was not seen in control subjects without RA (P = 0.15). IgG-CMV antibody levels did not differ between groups.Subjects whose serum IgG-EA antibody levels are elevated in the preclinical period will eventually develop RA, which suggests that EBV reactivation cycles are increased during the preclinical period of RA. A combination of RF and EBV reactivation may play an important role in the development of RA.

OBJECTIVE To evaluate the prevalence of elevations of anti-cyclic citrullinated peptide-3 (anti-CCP3) antibody, rheumatoid factor IgM (RF-IgM) and serum calprotectin (sCP) in pre-rheumatoid arthritis (RA) as well as the diagnostic accuracies of these biomarkers for the timing of diagnosis of future RA. METHODS A total of 215 RA cases, each with approximately three pre-RA diagnoses and one post-RA diagnosis serum sample, and controls were identified from the Department of Defense Serum Repository. All case samples and a single sample from each control subject were tested for anti-CCP3 (IgG), RF-IgM, and sCP. The diagnostic accuracies of biomarkers for future RA were evaluated. RESULTS Anti-CCP3, RF-IgM, and sCP were elevated in pre-RA, with anti-CCP3 and sCP significantly elevated compared with RF-IgM at the earliest time points. Within the cases, the combination of anti-CCP3 and RF-IgM positivity had a positive predictive value (PPV) of 35.6% for a diagnosis of RA in 3 years or less, which is significantly higher than the PPV of 18.7% for anti-CCP3 positivity alone (P < 0.001). A combination of anti-CCP3, RF-IgM, and sCP had the highest PPV (53.0%) for a diagnosis of RA in 3 years or less; however, this was not significantly higher than the PPV for anti-CCP3 and RF-IgM positivity (P = 0.248). CONCLUSION Anti-CCP3, RF-IgM, and sCP are elevated in pre-RA; furthermore, combinations of elevations of these biomarkers are more commonly seen in the period of less than or equal to 3 years to diagnosis. This may be considered in creating inclusion criteria in prevention trials in RA. In addition, the biologic relationships of these biomarkers in pre-RA need exploration.

Mitochondria are found in the extracellular space in rheumatoid arthritis (RA). However, whether mitochondria are a source of autoantigens in RA has not been carefully addressed. Thus, we investigated the presence and significance of anti-mitochondrial antibodies (AMA) in patients with RA.AMAs were measured in sera from three cross-sectional RA cohorts (n=95, n=192, and n=117) and healthy individuals (n=38, n=72, n=50) using a flow cytometry-based assay. Further, AMAs were detected using anti-mitofusin-1 (MFN1) IgG ELISA and Western blot. A longitudinal inception cohort, followed for a median of 8 years, was used to study disease progression.AMA levels were elevated in all three RA cohorts as compared to healthy individuals (p0.001, p0.05, and p0.01), with a range of 14-26% positivity. Levels of anti-MFN1 antibodies correlated with AMA levels (r=0.31, p=0.006) and were elevated in RA as compared to healthy individuals (p0.001). Presence of AMA was associated with erosive disease (p0.05) and interstitial lung disease (p0.01). Further, AMA levels could predict erosive disease (OR=4.59, p=0.006) and joint space narrowing (OR=3.08, p=0.02) independent of anti-citrullinated protein antibodies. Finally, anti-MFN1 antibodies identified seronegative patients developing erosive disease (OR=9.33, p=0.02).Our findings demonstrate the presence of novel autoantibodies targeting mitochondria in RA. AMAs stratified patients based on disease phenotype and predicted development of erosive disease, including in patients with seronegative disease. Our results highlight the essential role of mitochondria in RA pathogenesis and suggest a possible benefit of therapies targeting mitochondrial-mediated inflammation and clearance in these patients. This article is protected by copyright. All rights reserved.

The mucosal origins hypothesis of rheumatoid arthritis (RA) proposes a central role for mucosal immune responses in the initiation or perpetuation of the systemic autoimmunity that occurs with disease. However, the connection between the mucosa and systemic autoimmunity in RA remains unclear. Using dual immunoglobulin A (IgA) and IgG family plasmablast–derived monoclonal autoantibodies obtained from peripheral blood of individuals at risk for RA, we identified cross-reactivity between RA-relevant autoantigens and bacterial taxa in the closely related families Lachnospiraceae and Ruminococcaceae . After generating bacterial isolates within the Lachnospiraceae/Ruminococcaceae genus Subdoligranulum from the feces of an individual, we confirmed monoclonal antibody binding and CD4 + T cell activation in individuals with RA compared to control individuals. In addition, when Subdoligranulum isolate 7 but not isolate 1 colonized germ-free mice, it stimulated T H 17 cell expansion, serum RA–relevant IgG autoantibodies, and joint swelling reminiscent of early RA, with histopathology characterized by antibody deposition and complement activation. Systemic immune responses were likely due to mucosal invasion along with the generation of colon-isolated lymphoid follicles driving increased fecal and serum IgA by isolate 7, because B and CD4 + T cell depletion not only halted intestinal immune responses but also eliminated detectable clinical disease. In aggregate, these findings demonstrate a mechanism of RA pathogenesis through which a specific intestinal strain of bacteria can drive systemic autoantibody generation and joint-centered antibody deposition and immune activation.

Prevotella copri (Pc), a gut commensal, has been reported to be an immune relevant organism in individuals with rheumatoid arthritis (RA). Our goal was to evaluate anti-Pc antibody responses in our participant cohorts and determine when in the natural history of RA such responses develop.Serum levels of IgA and IgG anti-Pc-p27, an immunogenic Pc protein, were analyzed in study participants at-risk for the development of RA, those who transitioned to RA, in those with early RA (one year of disease), and in those with established RA, compared to matched controls. Additionally, levels of anti-Pc-p27 antibodies were evaluated in individuals stratified by RA-related autoantibody status.Overall, participants with RA had significantly higher levels of IgA anti-Pc-p27 antibodies and trends towards higher levels of IgG anti-Pc-p27 antibodies when compared to their matched controls. When stratified by early versus established RA, early RA participants had median values of IgG anti-Pc-p27 antibodies that were overall higher, whereas median values of IgA anti-Pc-p27 were statistically significantly higher in participants with established RA, compared with their matched controls. In the autoantibody specific analyses, the at-risk population with anti-CCP antibodies, but not RF, demonstrated trends towards increased levels of IgG anti-Pc-p27. Additionally, RA participants who were CCP+/RF+ had significantly increased levels of IgA anti-Pc-p27 antibodies and a trend toward levels of IgG anti-Pc-p27 antibodies when compared to their matched controls.These findings support a potential etiologic role for this microorganism in both RA preclinical evolution and the subsequent pathogenesis of synovitis.

OBJECTIVE To determine the association of polyunsaturated fatty acid (PUFA)-derived lipid mediators with progression from rheumatoid arthritis (RA)-related autoimmunity to inflammatory arthritis (IA). METHODS We conducted a prospective cohort study using data from the Studies of the Etiology of Rheumatoid Arthritis (SERA). SERA enrolled first-degree relatives (FDRs) of individuals with RA (FDR cohort) and individuals who screened positive for RA-related autoantibodies at health fairs (screened cohort). We followed up 133 anti-cyclic citrullinated peptide 3.1 (anti-CCP3.1)-positive participants, 29 of whom developed IA. Lipid mediators selected a priori were quantified from stored plasma samples using liquid chromatography tandem mass spectrometry. We fit multivariable Cox proportional hazards models for each lipid mediator as a time-varying variable. For lipid mediators found to be significantly associated with IA, we then examined interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor (TNF) as potential statistical mediators. RESULTS For every 1 natural log pg/ml increase in the circulating plasma levels of proinflammatory 5-HETE, the risk of developing IA increased by 241% (hazard ratio 2.41 [95% confidence interval 1.43-4.07]) after adjusting for age at baseline, cohort (FDR or screened), and shared epitope status. The models examining 15-HETE and 17-HDHA had the same trend but did not reach significance. We did not find evidence that the association between 5-HETE and IA risk was influenced by the proinflammatory cytokines tested. CONCLUSION In a prospective cohort of anti-CCP-positive individuals, higher levels of 5-HETE, an important precursor to proinflammatory leukotrienes, is associated with subsequent IA. Our findings highlight the potential significance of these PUFA metabolites in pre-RA populations.

The mucosal origins hypothesis of rheumatoid arthritis (RA) proposes a central role for mucosal immune responses in the initiation and/or perpetuation of the systemic autoimmunity that occurs with disease. However, the connection between the mucosa and systemic autoimmunity in RA remains unclear. Using dual IgA/IgG family plasmablast-derived monoclonal autoantibodies obtained from peripheral blood of individuals at-risk for RA, we identified cross-reactivity between RA-relevant autoantigens and bacterial taxa in the closely related families Lachnospiraceae and Ruminococcaceae. After generating bacterial isolates within Lachnospiraceae/Ruminococcaceae genus Subdoligranulum from the feces of an individual, we confirmed monoclonal antibody binding as well as MHC class II dependent CD4+ T cell activation in RA cases compared to controls. Additionally, when Subdoligranulum isolate 7 but not isolate 1 colonized germ-free mice, it stimulated Th17 cell expansion, serum RA-relevant IgG autoantibodies, and joint swelling reminiscent of early RA with histopathology characterized by antibody deposition and complement activation. Systemic immune responses were likely due to the generation of colon isolated lymphoid follicles (ILFs) driving increased fecal and serum IgA by isolate 7, as B and T cell depletion not only halted intestinal immune responses but also eliminated detectable clinical disease. In aggregate, these findings demonstrate one mucosal mechanism in RA through which an intestinal strain of bacteria can drive systemic autoantibody generation and joint-centered antibody deposition and immune activation.One-sentence summarySubdoligranulum spp. targeted by rheumatoid arthritis (RA)-relevant autoantibodies activate T cells in individuals with RA, and in mice stimulate autoantibodies and joint swelling associated with antibody deposition and complement activation.

OBJECTIVE The aim of this study was to determine the association of perceived stress with incident inflammatory arthritis (IA) defined as having at least 1 joint consistent with rheumatoid arthritis (RA)-like synovitis based on examination. METHODS We conducted a prospective cohort study in the Studies of the Etiologies of Rheumatoid Arthritis cohort. Participants without IA were recruited if they were a first-degree relative of an RA proband or screened positive for anti-citrullinated protein antibody. Perceived stress was measured using the Perceived Stress Scale-14 (PSS-14), in which scores can range from 0 to 56, and a higher score indicates greater perceived stress. The total PSS-14 score, as well as 2 subscores indicative of perceived distress and self-efficacy, were averaged across all study visits until development of IA or the last follow-up. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) of IA associated with average PSS-14 scores were obtained using Cox proportional hazards models. RESULTS The mean total PSS-14 score was 20.4. We found that a 1-point increase in the perceived distress score was significantly associated with a 10-percent increase in the risk of IA (adjusted HR 1.10 [95% CI 1.02-1.19]). Total PSS-14 and self-efficacy were not associated with IA risk (adjusted HR 1.05 [95% CI 0.99-1.10] and 1.04 [95% CI 0.91-1.18], respectively). CONCLUSION An association between perceived distress and incident IA was observed in this at-risk cohort. Replication of this finding in other preclinical and at-risk RA populations is needed.

Rheumatoid arthritis is an autoimmune disease that classically presents as a symmetrical inflammatory polyarthritis. Extra-articular manifestations are prevalent, with the lungs being the most common site [1], and interstitial lung disease (ILD) being the most severe form of pulmonary involvement. In some studies, the median survival of patients with rheumatoid arthritis and a usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography (HRCT) is around 3 years (similar to that in idiopathic pulmonary fibrosis (IPF) [2, 3]); however, in other studies, median survival is >7 years [4, 5]. When present, ILD accounts for 10–20% of all deaths in rheumatoid arthritis [6]., Age of ILD onset is similar in patients with RA-UIP and RA-NSIP but duration of RA before ILD onset differs https://bit.ly/3lgjfDJ

Rheumatoid arthritis (RA) is a common condition affecting approximately 1% of the general population. RA is a multisystem disorder that causes progressive articular destruction through synovial inflammation. One of the most common extraarticular manifestations of RA is pulmonary involvement, where all compartments of the pulmonary system can be impacted (e.g., pulmonary vasculature, pleura, parenchyma, and the airways). Although it has been known for decades that a portion of patients with RA develop interstitial lung disease, and recent advancements in understanding the genetic risk and treatment for RA-interstitial lung disease have drawn attention, more recent data have begun to highlight the significance of airway disease in patients with RA. Yet, little is known about the underlying pathogenesis, clinical impact, or optimal treatment strategies for airway disease in RA. This review will focus on airway disease involvement in patients with RA by highlighting areas of clinical inquiry for pulmonologists and rheumatologists and discuss areas for future research. Finally, we discuss a potential screening algorithm for providers when approaching patients with RA with respiratory complaints.

Objective To evaluate patterns of elevations of isotypes of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) pre-rheumatoid arthritis (RA) diagnosis and post-RA diagnosis. Methods Using the Department of Defense Serum Repository we identified 214 RA cases and 210 matched controls. Up to 3 pre-RA diagnosis and 1 post-RA diagnosis serum samples per subject were tested for RF and for IgA, IgG, and IgM ACPAs. The timing and trajectories of elevations of autoantibodies were evaluated. Results Autoantibody levels were elevated in cases versus controls a mean of 17.9 years before RA diagnosis for IgG ACPA, 14.2 years for IgA-RF, 7.2 years for IgM-RF, 6.2 years for IgA ACPA, and 5.0 years for both IgM ACPA and IgG-RF (P 2 years post-RA diagnosis; P = 0.04). All autoantibody levels demonstrated an early initial elevation, a period of stability, then an increase immediately before RA diagnosis. A pre-RA endotype of early elevation of autoantibodies was associated with increased use of biologic therapy, and a higher prevalence of sicca symptoms and lung disease post-RA diagnosis. Conclusion Differences in patterns of elevations of autoantibody isotypes have implications for understanding the pathophysiology of RA development. These include understanding what factors drive initial autoantibody elevations compared to what factors (including mucosal) drive later increases in autoantibody levels and a transition to clinically apparent RA, and how pre-RA endotypes may influence post-RA diagnosis phenotypes.

Objective.We investigated the association of age and anticyclic citrullinated peptide antibodies (anti-CCP) in subjects without rheumatoid arthritis (RA).Methods.Serum was tested for anti-CCP3.1 (IgG/IgA) in 678 first-degree relatives (FDR) of patients with RA and 330 patients with osteoarthritis (OA). Individual isotypes (anti–CCP-IgA and anti–CCP-IgG) were also tested in all FDR.Results.In FDR, increasing age was significantly associated with positivity for anti-CCP3.1 (per year, OR 1.03) and anti–CCP-IgA (per year, OR 1.05) but not anti–CCP-IgG. In FDR and OA subjects, anti-CCP3.1 prevalence was significantly increased after age 50 years.Conclusion.Increasing age in individuals without RA should be considered in the interpretation of anti-CCP3.1 positivity.

Background Autoimmune disease prevention requires tools to assess an individual's risk of developing a specific disease. One tool is disease-associated autoantibodies, which accumulate in an asymptomatic preclinical period. However, patients sometimes exhibit autoantibodies associated with a different disease classification. When and how these alternative autoantibodies first appear remain unknown. This cross-sectional study characterizes alternative autoimmunity, and associated genetic and environmental factors, in unaffected first-degree relatives (FDRs) of patients, who exhibit increased future risk for the same disease. Methods Samples (n = 1321) from disease-specific autoantibody-positive (aAb+) systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and type 1 diabetes (T1D) patients; and unaffected aAb+ and autoantibody-negative (aAb–) SLE and RA FDRs were tested for SLE, RA, and T1D aAbs, as well as anti-tissue transglutaminase, anti-cardiolipin and anti-thyroperoxidase. FDR SLE and RA genetic risk scores (GRS) were calculated. Findings Alternative autoimmunity occurred in SLE patients (56%) and FDRs (57·4%), RA patients (32·6%) and FDRs (34·8%), and T1D patients (43%). Expanded autoimmunity, defined as autoantibodies spanning at least two other diseases, occurred in 18·5% of SLE patients, 16·4% of SLE FDRs, 7·8% of RA patients, 5·3% of RA FDRs, and 10·8% of T1D patients. SLE FDRs were more likely to have alternative (odds ratio [OR] 2·44) and expanded (OR 3·27) autoimmunity than RA FDRs. Alternative and expanded autoimmunity were associated with several environmental exposures. Alternative autoimmunity was associated with a higher RA GRS in RA FDRs (OR 1·41), and a higher SLE GRS in aAb+ RA FDRs (OR 1·87), but not in SLE FDRs. Interpretation Autoimmunity commonly crosses disease-specific boundaries in systemic (RA, SLE) and organ-specific (T1D) autoimmune diseases. Alternative autoimmunity is more common in SLE FDRs than RA FDRs, and is influenced by genetic and environmental factors. These findings have substantial implications for preclinical disease pathogenesis and autoimmune disease prevention studies. Fund NIH U01AI101981, R01AR051394, U19AI082714, P30AR053483, P30GM103510, U54GM104938, U01AI101934, R01AI024717, U01AI130830, I01BX001834, & U01HG008666.

Interstitial lung disease (ILD) is a common manifestation in connective tissue diseases (CTD), such as rheumatoid arthritis (RA), systemic sclerosis (SSc) and inflammatory myositis (IM). ILD is associated with significant morbidity and mortality in nearly all CTD highlighting the critical need for effective treatment strategies in this patient population. In this review, we will summarize the approach to treatment when there is concern for CTD-ILD and highlight recent advancements in therapeutics within various specific CTD-ILDs.

Background Mucosal sites are hypothesized to play a role in the development of rheumatoid arthritis (RA). Since serum anti-peptidylarginine deiminase (PAD)4 antibodies, including a subset that cross-react with PAD3 (PAD3/4), are specific for RA and associate with severe disease, we sought to examine whether anti-PAD4 and anti-PAD3/4 antibodies were present in the lung and oral mucosa of subjects with RA and “at-risk” for RA. Methods We included 37 RA, 25 healthy control, and 46 subjects “at-risk” for RA based on familial RA and/or serum anti-citrullinated protein antibody (ACPA) positivity. Paired serum, sputum, and saliva were evaluated for anti-PAD4 and anti-PAD3/4 using immunoprecipitation and ACPA using ELISA. Immunoglobulins (Ig) were purified from representative samples, and their effect on citrullination of histone H3 by recombinant human PAD4 was measured by anti-citH3 immunoblot. Results Anti-PAD4 antibodies were detected in the serum of 6/37 (16.2%), sputum of 3/37 (8.1%), and saliva of 3/33 (9.1%) RA subjects and in the serum and sputum of 1/46 (2.2%) at-risk subjects. None of the healthy controls had anti-PAD4 antibodies at any site. Serum, sputum, and salivary anti-PAD4 antibodies were more prevalent in RA subjects with RA duration >2 years. Purified antibodies from representative anti-PAD4-positive and anti-PAD3/4-positive sputum were primarily of the IgA isotype and able to increase PAD4 enzymatic activity. Conclusions Anti-PAD4 antibodies are present in the sputum and saliva of a portion of RA patients and are infrequent in at-risk subjects. Importantly, the ability of anti-PAD4, and particularly anti-PAD3/4, antibodies in the sputum to enhance PAD4 enzymatic activity suggests that anti-PAD4 may play an active role in the RA lung.

OBJECTIVE Mechanisms leading to anti-citrullinated protein antibody (ACPA) generation in rheumatoid arthritis (RA) are hypothesized to originate in the lung. We undertook this study to understand associations between neutrophil extracellular trap (NET) formation in the lung and local ACPA generation in subjects at risk of developing RA. METHODS Induced sputum was collected from 49 subjects at risk of developing RA, 12 patients with RA, and 18 controls. Sputum neutrophils were tested for ex vivo NET formation, and sputum-induced NET formation of control neutrophils was measured using immunofluorescence imaging. Sputum macrophages were tested for ex vivo endocytosis of apoptotic and opsonized cells. Levels of ACPA, NET remnants, and inflammatory proteins were quantified in sputum supernatant. RESULTS Spontaneous citrullinated histone H3 (Cit-H3)-expressing NET formation was higher in sputum neutrophils from at-risk subjects and RA patients compared to controls (median 12%, 22%, and 0%, respectively; P < 0.01). In at-risk subjects, sputum IgA ACPA correlated with the percentage of neutrophils that underwent Cit-H3+ NET formation (r = 0.49, P = 0.002) and levels of Cit-H3+ NET remnants (r = 0.70, P < 0.001). Reduced endocytic capacity of sputum macrophages was found in at-risk subjects and RA patients compared to controls. Using a mediation model, we found that sputum inflammatory proteins were associated with sputum IgA ACPA through a pathway mediated by Cit-H3+ NET remnants. Sputum-induced Cit-H3+ NET formation also correlated with sputum levels of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor in at-risk subjects, suggesting a causal relationship. CONCLUSION These data support a potential mechanism for mucosal ACPA generation in subjects at risk of developing RA, whereby inflammation leads to increased citrullinated protein-expressing NETs that promote local ACPA generation.

SUMMARYRheumatoid arthritis (RA) is an autoimmune disease characterized in seropositive individuals by the presence of anti-cyclic citrullinated protein (CCP) antibodies. RA is linked to the intestinal microbiota, yet the association of microbes with CCP serology and their contribution to RA is unclear. We describe intestinal phage communities of individuals at risk for developing RA, with or without anti-CCP antibodies, whose first degree relatives have been diagnosed with RA. We show that at-risk individuals harbor intestinal phage compositions that diverge based on CCP serology, are dominated by Lachnospiraceae phages, and originate from disparate ecosystems. These phages encode unique repertoires of auxiliary metabolic genes (AMGs) which associate with anti-CCP status, suggesting that these phages directly influence the metabolic and immunomodulatory capability of the microbiota. This work sets the stage for the use of phages as preclinical biomarkers and provides insight into a possible microbial-based causation of RA disease development.

OBJECTIVES: Literature suggests that neutrophils of patients with rheumatoid arthritis (RA) are primed to respond to N-formyl methionine group (formylated peptides). Animal models indicate that formylated peptides contribute to joint damage via neutrophil recruitment and inflammation in joints. Non-steroidal anti-inflammatory drugs are also known to inhibit formyl peptide-induced neutrophil activation. The predominant source of formylated peptides in sterile inflammatory conditions like RA is mitochondria, organelles with prokaryotic molecular signatures. However, there is no direct evidence of mitochondrial formyl peptides (mtNFPs) in the circulation of patients with RA and their potential role in neutrophil-mediated inflammation in RA, including their clinical significance. METHODS: Levels of mtNFPs (total fMet, MT-ND6) were analyzed using ELISA in plasma and serum obtained from patients in 3 cross-sectional RA cohorts (n=275), a longitudinal inception cohort (n=192) followed for a median of 8 years, and age/gender-matched healthy controls (total n=134). Neutrophil activation assays were done in the absence or presence of formyl peptide receptor 1 (FPR1) inhibitor cyclosporine H. RESULTS: Elevated levels of total fMet were observed in the circulation of patients with RA as compared to healthy controls (p

Many autoimmune diseases display sex differences in epidemiology, presentation, and prognosis. Rheumatoid arthritis (RA) is three times more common in women and RA is generally more severe in women compared to men. Systemic lupus erythematosus is eight times more common in women and the distribution of lupus-related organ involvement differs by sex. In contrast, ankylosing spondylitis (AS) is more common in men and the clinical presentation of AS differs by sex. In addition, some of the medications used to treat autoimmune diseases have teratogenic effects; appropriate contraception should be included in each patient’s treatment plan. In clinical practice, it is important to consider sex differences in autoimmune diseases, particularly differences in initial clinical presentation and prognosis, because they can influence development of a differential diagnosis and, in established disease, can alter patient counseling regarding expectations for the disease course.

PURPOSE OF REVIEW: This review will summarize recent data defining the relationship between rheumatoid arthritis (RA) and the microbiome at mucosal sites throughout the body. It will highlight what is known, what is speculated, and current knowledge gaps regarding the microbiome in RA. RECENT FINDINGS: An extensive relationship between the microbiome and immune cell function can influence RA-related inflammation and T cell and B cell biology. Studies are beginning to characterize microbial changes in individuals who are at risk for RA, which is a critical element needed to understand the influence of the microbiome on RA pathogenesis. SUMMARY: Expanding our understanding of the microbiome in RA beyond the bacteria at the gut and oral mucosae into the lung and urogenital surfaces, including viral and fungal components, and establishing the relationship across mucosal sites will be critical in future work. Importantly, approaches to manipulate the microbiome could lead to novel therapeutic and preventive strategies.

BackgroundPhysical activity (PA) in pre-clinical rheumatoid arthritis (RA) is associated with lower RA risk and disease severity. Yet, PA in RA patients is less than in counterparts without RA, which can be attributed partly to symptoms of inflammatory arthritis. Therefore, we investigated whether joint swelling, stiffness, or pain were associated with PA in first-degree relatives (FDRs) of RA patients, a population at higher risk for future RA.MethodsWe evaluated associations of joint stiffness, joint swelling, and joint pain with PA time in 268 FDRs with ≥2 visits over an average 1.2 years. Clinicians confirmed joint swelling. Participants self-reported joint stiffness and/or pain. PA during a typical 24-hour day was quantified via questionnaire, weighted to reflect metabolic expenditure, where 24 hours was the minimum PA time. Linear mixed models evaluated associations between symptoms and change in PA over time, adjusting for age, sex, race, body mass index, smoking, and RA-related autoantibodies.ResultsAverage weighted PA time was 37±7 hours. In cross-sectional analysis, PA time was 1.3±0.9 hours higher in FDRs reporting joint pain (p=0.15); and 0.8±1.6 and 0.4±1 hours lower in FDRs with joint swelling (p=0.60) and stiffness (p=0.69), respectively. Longitudinally, adjusting for baseline PA time, baseline symptoms were not significantly associated with changes in PA time. However, on average over time, joint stiffness and pain were associated with lower PA time (pinteraction=0.0002, pinteraction=0.002), and joint swelling was associated with higher PA time (pinteractionConclusionBaseline symptoms did not predict future PA time, but on average over time, joint symptoms influenced PA time.

ObjectivesLittle is known about the likelihood of developing inflammatory arthritis (IA) in individuals who screen autoantibody positive (aAb+) in a non-clinical research setting.MethodsWe screened for serum cyclic citrullinated peptide antibody (anti-CCP) and rheumatoid factor isotype aAbs in subjects who were at increased risk for rheumatoid arthritis (RA) because they are a first-degree relative of an individual with classified RA (n=1780). We evaluated combinations of aAbs and high titre aAbs, as defined by 2-times (2 x) the standard cut-off and an optimal cut-off, as predictors of our two outcomes, aAb+ persistence and incident IA.Results304 subjects (17.1%) tested aAb+; of those, 131 were IA-free and had at least one follow-up visit. Sixty-four per cent of these tested aAb+ again on their next visit. Anti-CCP+ at levels ≥2 x the standard cut-off was associated with 13-fold higher likelihood of aAb +persistence. During a median of 4.4 years (IQR: 2.2–7.2), 20 subjects (15.3%) developed IA. Among subjects that screened anti-CCP+ at ≥ 2 x or ≥an optimal cut-off, 32% and 26% had developed IA within 5 years, respectively. Both anti-CCP cut-offs conferred an approximate fourfold increased risk of future IA (HR 4.09 and HR 3.95, pConclusionsThese findings support that aAb screening in a non-clinical setting can identify RA-related aAb+ individuals, as well as levels and combinations of aAbs that are associated with higher risk for future IA. Monitoring for the development of IA in aAb+ individuals and similar aAb testing approaches in at-risk populations may identify candidates for prevention studies in RA.

Additional file 1: Figure S1. Analysis of effect of methotrexate on TL1A levels from a second independent patient cohort. TL1A was measured in serum from an independent cohort of patients with RA treated with MTX for 4 months (66 good/moderate EULAR responders, 18 non-responders).

Additional file 2: Figure S2. Micro-CT Scoring system for erosions and joint damage (MCTS). A scoring system was devised for micro-CT measurements of hind paw joint scores incorporating a score for the ankle/tarsus, MTP, and distal joints with a total score of 0–30 points.

Additional file 3: Table S1. Demographic characteristics of SNUH cohort (data shown in Fig. 2 D-F and Fig. 3 B-D). Sr, serum; SF, synovial fluid; ESR, erythrocyte sedimentation rate; hsCRP, high sensitive C-reactive protein; RF, rheumatoid factor. Table S2. Demographic characteristics of patient subgroups from the SERA cohort.

Objective The location and mechanisms involved in the initial generation of autoantibodies to citrullinated and noncitrullinated proteins/peptides during the natural history of rheumatoid arthritis (RA) development is incompletely understood. This study sought to explore individual antibody responses to citrullinated and noncitrullinated proteins/peptides in the sputum and associations with neutrophil extracellular traps (NETs) in subjects at risk for the future development of RA. Methods Serum and sputum samples were obtained from 41 RA-free subjects who were considered at risk for the development of RA based on familial or serologic risk factors, from 20 subjects classified as having RA, and from 22 healthy control subjects. Samples were evaluated using a bead-based array for IgG reactivity to 29 citrullinated proteins/peptides and 21 noncitrullinated proteins/peptides. Cutoff levels for antibody positivity were established in a separate control group. NET levels in the sputum were measured using sandwich enzyme-linked immunosorbent assays that quantitate DNA-myeloperoxidase and DNA-neutrophil elastase complexes. Results In at-risk subjects, antibody responses to the citrullinated forms of fibrinogen, apolipoprotein E, and fibronectin were highly prevalent. The most citrulline-specific antibodies in the sputum of at-risk subjects were those to fibrinogen, vimentin, and peptides of fibrinogen A and apolipoprotein A1. Patterns of sputum autoantibody positivity differed between at-risk subjects and subjects with RA. In at-risk subjects, increasing sputum NET levels significantly correlated with several citrullinated and some noncitrullinated antibody reactivities. Conclusion These findings suggest that sputum antibody reactivity to particular citrullinated and noncitrullinated proteins/peptides is specific for RA and for subjects at risk of RA, and the association of these proteins/peptides with NETs may be a key feature of early RA-related autoimmunity in the lung. These results further support the hypothesis that the lung plays a role in early RA-related autoimmunity.

Objectives Higher circulating omega-3 fatty acids (n-3 FAs) are associated with a lower prevalence of anti-CCP antibodies and RF in subjects without RA. We examined whether, in anti-CCP+ subjects, n-3 FAs also play a role in development of inflammatory arthritis (IA). Methods At Colorado-based health fairs from 2008 to 2014, participants without a previous diagnosis of RA who were anti-CCP3+ (n = 47) were recruited into a follow-up study; symptom assessments and joint examinations were conducted every 6 months for the determination of IA. We measured n-3 FAs as a percentage of total lipids in red blood cell membranes (n-3 FA%) at each visit. Results We detected IA in 10 anti-CCP3+ subjects (21%) at the baseline visit. Increased total n-3 FA% in red blood cell membranes [odds ratio (OR) = 0.09, 95% CI: 0.01, 0.76], specifically docosapentaenoic acid (OR = 0.16, 95% CI: 0.03, 0.83) and docosahexaenoic acid (OR = 0.23, 95% CI: 0.06, 0.86), was associated with a lower odds of IA at the baseline visit, adjusting for n-3 FA supplement use, current smoking, RF+, elevated CRP+ and shared epitope. We followed 35 of the anti-CCP3+ subjects who were IA negative at baseline and detected 14 incident IA cases over an average of 2.56 years of follow-up. In a time-varying survival analysis, increasing docosapentaenoic acid significantly decreased risk of incident IA (hazard ratio = 0.52, 95% CI: 0.27, 0.98), adjusting for age at baseline, n-3 FA supplement use, RF+, CRP+ and shared epitope. Conclusion n-3 FAs may potentially lower the risk of transition from anti-CCP positivity to IA, an observation that warrants further investigation.

Multiple genetic and environmental factors have been associated with an increased risk for rheumatoid arthritis (RA). Of these, the strongest associations have been seen with female sex, a family history of RA, the genetic factor the ‘shared epitope’ and with exposure to tobacco smoke. There is also renewed interest in mucosal inflammation and microbial factors as contributors to the development of RA. However, the identification of a ‘preclinical’ period of RA that can be defined as local or systemic autoimmunity as measured by autoantibodies and other biomarkers prior to the development of clinically-apparent synovitis suggests that the risk factors for RA are acting long prior to first clinical evidence of IA. As such, a major challenge to the field will be to investigate the full spectrum of the development of RA, from initiation and propagation of autoimmunity during preclinical RA and transition to clinically-apparent synovitis and classifiable RA, in order to determine which genetic and environmental factors are important at each stage of disease development. Understanding the exact role and timing of action of risk factors for RA is especially important given the advent of prevention trials in RA, and the hope that a full understanding of genetic and environmental factors in RA could lead to effective preventive interventions.

The primary manifestation of rheumatoid arthritis (RA) is articular disease; however, extra-articular disease can also occur. In particular, pulmonary disease is a leading cause of morbidity and mortality in individuals with RA. Herein, we will review the types, prevalence, risk factors, and potential pathophysiology of lung disease in individuals with established RA. We will also discuss the emerging understanding of potential role of the lung in the generation of RA-related autoantibodies during a period of disease development termed "pre-RA." Finally, we will discuss a research agenda outlining the next steps to improve our understanding and management of lung inflammation and lung disease throughout the natural history of RA.