A gene-environment interaction between smoking and shared epitope genes in HLA-DR provides a high risk of seropositive rheumatoid arthritis

Re-evaluation of dietary interventions in rheumatoid arthritis: can we improve patient conversations around food choices?

Rheumatoid arthritis (RA) is one of over 100 different types of autoimmune conditions. In RA, the cells of the immune system attack the tissue lining the joints, triggering inflammation. A large body of research suggests that the underlying trigger(s) of RA are unique to an individual. For example, increased risk of RA can be driven by smoking tobacco in one individual and mercury exposure in another. Due to the development of next-generation sequencing technology, the critical role of the microbiota in shaping RA risk has been elucidated. Therefore, it is surprising that diet, arguably the most important lever in shaping the gut microbiota, is ineffective in the treatment of RA, even in a sub-set of patients. To attempt to rationalise this apparent paradox, we conducted an umbrella review to address the question as to whether diet can affect outcomes in RA.

Differences in the expression of long noncoding RNAs in peripheral blood mononuclear cells indicate potential biomarkers for rheumatoid arthritis

OBJECTIVE

Long noncoding RNAs (lncRNAs) play an increasingly important role in various autoimmune diseases. We aimed to characterize the expression profiles of lncRNAs in peripheral blood mononuclear cells (PBMCs) from RA patients and to assess the potential of these lncRNAs as RA biomarkers.

METHODS

Whole-transcriptome sequencing was used to establish a lncRNA expression profile. A total of 155 RA patients, 145 healthy controls, 59 systemic lupus erythematosus (SLE) patients and 59 primary Sjögren's syndrome (pSS) patients were recruited for this study. Four candidate lncRNAs (linc00152, lnc-ADM-1, ITSN1-2, and lnc-FTH1-7) were validated via qRT-PCR in independent samples, and their expression, association with RA clinical features and value as RA biomarkers were evaluated.

RESULTS

Linc00152 and lnc-ADM-1 exhibited upregulated expression (p = 0.001, p = 0.014, respectively), while ITSN1-2 and lnc-FTH1-7 exhibited downregulated expression (both p < 0.001, respectively) in RA patients compared to controls. Lnc-ADM-1 and lnc-FTH1-7 expression correlated positively with the C4 level (p = 0.016 and p = 0.012, respectively). ITSN1-2 levels were negatively associated with CRP levels (p = 0.024). Linc00152, lnc-ADM-1, ITSN1-2, and lnc-FTH1-7 showed potential as RA biomarkers, with the four-lncRNA panel distinguishing RA patients from controls, SLE patients, or pSS patients (AUC = 0.886, 0.746, and 0.749, respectively).

CONCLUSION

The altered expression of linc00152, lnc-ADM-1, ITSN1-2 and lnc-FTH1-7 in RA patients suggested that these genes may serve as potential biomarkers for RA and could be involved in its pathogenesis.

Identification of citrullinated α1-antitrypsin (A1AT) in saliva in a mouse model of rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) is an autoimmune disease characterized by progressive joint destruction. Early diagnosis and treatment, before joint deformation or destruction occurs, are crucial. Identifying novel biomarkers for RA in saliva could potentially enable early detection of the disease, prior to its onset.

METHODS

We conducted a comprehensive proteomic analysis of salivary proteins in a mouse model of RA. Proteins were identified using western blotting and enzyme-linked immunosorbent assay in the serum, saliva, and ankle joints of DBA/1JJmsSlc mice, a model of RA. Ankle joints and submandibular glands were stained with hematoxylin and eosin and immunostained, and the results were compared with those of control mice.

RESULTS

Citrullinated alpha-1 antitrypsin (A1AT, 46 kDa) was commonly detected in the saliva, serum, and ankle joints of mice with severe RA and was confirmed through proteomic analysis. Western blotting showed a band corresponding to 46 kDa in the serum, saliva, and ankle joints. Immunostaining of the ankle joints with the A1AT antibody showed a strong positive signal in the synovium.

CONCLUSIONS

In DBA/1JJmsSlc mice, cyclic citrullinated peptide antibodies and A1AT may be involved in citrullination and contribute to the development and severity of RA, making them valuable treatment targets requiring further study.

Explainable deep learning for disease activity prediction in chronic inflammatory joint diseases

Analysing complex diseases such as chronic inflammatory joint diseases (CIJDs), where many factors influence the disease evolution over time, is a challenging task. CIJDs are rheumatic diseases that cause the immune system to attack healthy organs, mainly the joints. Different environmental, genetic and demographic factors affect disease development and progression. The Swiss Clinical Quality Management in Rheumatic Diseases (SCQM) Foundation maintains a national database of CIJDs documenting the disease management over time for 19'267 patients. We propose the Disease Activity Score Network (DAS-Net), an explainable multi-task learning model trained on patients' data with different arthritis subtypes, transforming longitudinal patient journeys into comparable representations and predicting multiple disease activity scores. First, we built a modular model composed of feed-forward neural networks, long short-term memory networks and attention layers to process the heterogeneous patient histories and predict future disease activity. Second, we investigated the utility of the model's computed patient representations (latent embeddings) to identify patients with similar disease progression. Third, we enhanced the explainability of our model by analysing the impact of different patient characteristics on disease progression and contrasted our model outcomes with medical expert knowledge. To this end, we explored multiple feature attribution methods including SHAP, attention attribution and feature weighting using case-based similarity. Our model outperforms temporal and non-temporal neural network, tree-based, and naive static baselines in predicting future disease activity scores. To identify similar patients, a k-nearest neighbours regression algorithm applied to the model's computed latent representations outperforms baseline strategies that use raw input features representation.

Comprehensive insights into rheumatoid arthritis: Pathophysiology, current therapies and herbal alternatives for effective disease management

Rheumatoid arthritis is a chronic autoimmune inflammatory disease characterized by immune response overexpression, causing pain and swelling in the synovial joints. This condition is caused by auto-reactive antibodies that attack self-antigens due to their incapacity to distinguish between self and foreign molecules. Dysregulated activity within numerous signalling and immunological pathways supports the disease's development and progression, elevating its complexity. While current treatments provide some alleviation, their effectiveness is accompanied by a variety of adverse effects that are inherent in conventional medications. As a result, there is a deep-rooted necessity to investigate alternate therapeutic strategies capable of neutralizing these disadvantages. Medicinal herbs display a variety of potent bioactive phytochemicals that are effective in the complementary management of disease, thus generating an enormous potency for the researchers to delve deep into the development of novel phytomedicine against autoimmune diseases, although additional evidence and understanding are required in terms of their efficacy and pharmacodynamic mechanisms. This literature-based review highlights the dysregulation of immune tolerance in rheumatoid arthritis, analyses the pathophysiology, elucidates relevant signalling pathways involved, evaluates present and future therapy options and underscores the therapeutic attributes of a diverse array of medicinal herbs in addressing this severe disease.

Single-cell insights into immune dysregulation in rheumatoid arthritis flare versus drug-free remission

Immune-mediated inflammatory diseases (IMIDs) are typically characterised by relapsing and remitting flares of inflammation. However, the unpredictability of disease flares impedes their study. Addressing this critical knowledge gap, we use the experimental medicine approach of immunomodulatory drug withdrawal in rheumatoid arthritis (RA) remission to synchronise flare processes allowing detailed characterisation. Exploratory mass cytometry analyses reveal three circulating cellular subsets heralding the onset of arthritis flare - CD45RO+PD1hi CD4+ and CD8+ T cells, and CD27+CD86+CD21- B cells - further characterised by single-cell sequencing. Distinct lymphocyte subsets including cytotoxic and exhausted CD4+ memory T cells, memory CD8+CXCR5+ T cells, and IGHA1+ plasma cells are primed for activation in flare patients. Regulatory memory CD4+ T cells (Treg cells) increase at flare onset, but with dysfunctional regulatory marker expression compared to drug-free remission. Significant clonal expansion is observed in T cells, but not B cells, after drug cessation; this is widespread throughout memory CD8+ T cell subsets but limited to the granzyme-expressing cytotoxic subset within CD4+ memory T cells. Based on our observations, we suggest a model of immune dysregulation for understanding RA flare, with potential for further translational research towards novel avenues for its treatment and prevention.

Adherence to dietary guidelines, and the risk of developing rheumatoid arthritis: results from a nested case-control study

OBJECTIVES

To examine the relationship between adherence to dietary guidelines and the risk of developing RA.

METHODS

Participants in the Malmö Diet and Cancer Study (MDCS) cohort diagnosed with RA were identified through register linkage and validated in a structured review. Four controls per case were selected, matched for sex, year of birth, and year of inclusion in the MDCS. Diet was assessed at baseline (1991-1996) using a validated diet history method. A Diet Quality Index (DQI) based on adherence to the Swedish dietary guidelines including intakes of fibre, vegetables and fruits, fish and shellfish, saturated fat, polyunsaturated fat, and sucrose, was used. The associations between the DQI and its components and the risk of RA were assessed using conditional logistic regression analysis, adjusting for total energy intake, smoking, leisure time physical activity and alcohol consumption.

RESULTS

We identified 172 validated cases of incident RA in the cohort. Overall adherence to the dietary guidelines was not associated with the risk of RA. Adherence to recommended fibre intake was associated with decreased risk of RA in crude and multivariable-adjusted analyses, with odds ratios (ORs) 0.60 (95% CI 0.39, 0.93) and 0.51 (95% CI 0.29, 0.90), respectively, compared with subjects with non-adherence.

CONCLUSIONS

Reaching the recommended intake level of dietary fibre, but not overall diet quality, was independently associated with decreased risk of RA. Further studies are needed to assess the role of different food sources of dietary fibre in relation to risk of RA and the underlying mechanisms.

Maternal rheumatoid arthritis and risk of autism in the offspring

BACKGROUND

Maternal Rheumatoid Arthritis (RA) is suggested to increase the risk of Autism Spectrum Disorder (ASD) in the offspring, mainly through inflammation/autoimmunity, but the association is unclear. A prospective population-based cohort study was implemented to examine the association between maternal RA and offspring ASD.

METHODS

We included all children born alive in Sweden from 1995 to 2015, followed up through 2017. Diagnoses of ASD and RA were clinically ascertained from National Patient Register. We quantified the association by hazard ratios (HR) and two-sided 95% confidence intervals (CI), from Cox regression after detailed adjustment for potential confounders. We examined RA serostatus, etiological subgroups and the timing of exposure. To closer examine the underlying mechanism for the association, we included a negative control group for RA, arthralgia, with similar symptomology as RA but free from inflammation/autoimmunity.

RESULTS

Of 3629 children born to mothers with RA, 70 (1.94%) were diagnosed with ASD, compared to 28 892 (1.92%) of 1 503 908 children born to mothers without RA. Maternal RA before delivery was associated with an increased risk of offspring ASD (HR = 1.43, 95% CI 1.11-1.84), especially for seronegative RA (HR = 1.61, 95% CI 1.12-2.30). No similar association was observed for paternal RA, maternal sisters with RA, or RA diagnosed after delivery. Maternal arthralgia displayed as high risks for offspring ASD as did maternal RA (HR = 1.41, 95% CI 1.24-1.60).

CONCLUSIONS

In Sweden, maternal RA before delivery was associated with an increased risk of offspring ASD. The comparable association between maternal arthralgia and ASD risk suggests other pathways of risk than autoimmunity/inflammation, acting jointly or independently of RA.

Network-Based In Silico Analysis of New Combinations of Modern Drug Targets with Methotrexate for Response-Based Treatment of Rheumatoid Arthritis

BACKGROUND

Methotrexate (MTX), sulfonamides, hydroxychloroquine, and leflunomide have consistently resulted in remission with relatively mild to moderate adverse effects in patients with rheumatoid arthritis (RA). Modern medications outperform traditional treatments in that they target the pathological processes that underlie the development of RA.

METHODS

Following PRISMA guidelines, the authors accomplished a systematic review of the clinical efficacy of RA drugs, including the biologics such as Tumor Necrosis Factor-alpha inhibitors (TNF-α i) like Etanercept, Infliximab, Golimumab, and Adalimumab, kinase inhibitors (JAK inhibitors including Baricitinib and Tofacitanib), SyK inhibitors like Fos-tamatinib, MAPK inhibitors such as Talmapimod, T-cell inhibitors (Abatacept), IL6 blockers (Tocilizumab), and B cells depleters (Rituximab). These drugs have been found to increase remission rates when combined with MTX. A bioinformatics-based network was designed applying STRING-MODEL and the DrugBank database for the aforementioned drugs and MTX and, finally, employed for this systematic review.

RESULTS

Current research demonstrates that non-TNF-α inhibitor biologicals are particularly helpful in treating patients who did not respond well to conventional medications and TNF-α inhibitors. Despite being effective, these innovative drugs have a higher chance of producing hazardous side effects. The in silico investigations suggested an uncovered molecular interaction in combining MTX with other biological drugs. The STRING-MODEL showed that DHFR, TYMS, and ATIC, as the receptors of MTX, interact with each other but are not connected to the major interacted receptors.

CONCLUSIONS

New game-changing drugs including Mavrilimumab, Iguratimod, Upadacitinib, Fenebrutinib, and nanoparticles may be crucial in controlling symptoms in poorly managed RA patients. Emerging therapeutic targets like Toll-like 4 receptors, NLRP3 inflammasome complexes, and mesenchymal stem cells can further transform RA therapy.

Inappropriate treatment response to DMARDs: A pathway to difficult-to-treat rheumatoid arthritis

In recent years, difficult-to-treat rheumatoid arthritis (D2T RA) has attracted significant attention from rheumatologists due to its poor treatment response and the persistent symptoms or signs experienced by patients. The therapeutic demands of patients with D2T RA are not properly met due to unclear pathogenic causes and a lack of high-quality data for current treatment options, creating considerable management difficulties with this patient population. This review describes the clinical challenges associated with disease-modifying antirheumatic drugs (DMARDs) and explores contributing factors associated with inappropriate response to DMARDs that may lead to D2T RA and related immunological dysregulation. It is now understood that D2T RA is a highly heterogeneous pathological status that involves multiple factors. These factors include but are not limited to genetics, environment, immunogenicity, comorbidities, adverse drug reactions, inappropriate drug application, poor adherence, and socioeconomic status. Besides, these factors may manifest in the selection and utilization of specific DMARDs, either individually or in combination, thereby contributing to inadequate treatment response. Finding these variables may offer hints for enhancing DMARD therapy plans and bettering the condition of D2T RA patients.

Familial risk of seropositive rheumatoid arthritis and interaction with smoking: a population-based cohort study

OBJECTIVES

We evaluated the familial risk of seropositive rheumatoid arthritis (RA) and examined interactions between family history and smoking.

METHODS

Using the National Health Insurance and Health Screening Program databases, which include information on familial relationships and lifestyle factors, we identified 5 524 403 individuals with first-degree relatives (FDRs) from 2002-2018. We calculated familial risk using hazard ratios (HRs) with 95% CIs which compare the risk of individuals with and without affected FDRs. Interactions between smoking and family history were assessed on an additive scale using the relative excess risk due to interaction (RERI).

RESULTS

Individuals with affected FDR had 4.52-fold (95% CI 3.98, 5.12) increased risk of disease compared with those with unaffected FDR. Familial risk adjusted for lifestyle factors decreased slightly (HR 4.49), suggesting that a genetic contribution is the predominant driver in the familial aggregation of RA. Smoking was associated with an increased risk of disease that was more pronounced among heavy (HR 1.92 95% CI 1.70, 2.18) compared with moderate (HR 1.15 95% CI 1.04, 1.28) smoking. In the interaction analysis, the risk associated with the combined effect of smoking and family history was higher than the sum of their individual effects, though statistically non-significant (RERI 1.30 95% CI ‒0.92, 3.51). Heavy smokers with a positive family history showed a prominent interaction (RERI 4.13 95% CI ‒0.88, 9.13) which exceeded moderate smokers (RERI 0.61 95% CI ‒1.90, 3.13), suggesting a dose-response interaction pattern.

CONCLUSION

Our findings indicate the possibility of an interaction between RA-associated genes and smoking.

Immune-mediated lung diseases: A narrative review

The role of immunity in the pathogenesis of various pulmonary diseases, particularly interstitial lung diseases (ILDs), is being increasingly appreciated as mechanistic discoveries advance our knowledge in the field. Immune-mediated lung diseases demonstrate clinical and immunological heterogeneity and can be etiologically categorized into connective tissue disease (CTD)-associated, exposure-related, idiopathic, and other miscellaneous lung diseases including sarcoidosis, and post-lung transplant ILD. The immunopathogenesis of many of these diseases remains poorly defined and possibly involves either immune dysregulation, abnormal healing, chronic inflammation, or a combination of these, often in a background of genetic susceptibility. The heterogeneity and complex immunopathogenesis of ILDs complicate management, and thus a collaborative treatment team should work toward an individualized approach to address the unique needs of each patient. Current management of immune-mediated lung diseases is challenging; the choice of therapy is etiology-driven and includes corticosteroids, immunomodulatory drugs such as methotrexate, cyclophosphamide and mycophenolate mofetil, rituximab, or other measures such as discontinuation or avoidance of the inciting agent in exposure-related ILDs. Antifibrotic therapy is approved for some of the ILDs (e.g., idiopathic pulmonary fibrosis) and is being investigated for many others and has shown promising preliminary results. A dire need for advances in the management of immune-mediated lung disease persists in the absence of standardized management guidelines.

The human bone marrow plasma cell compartment in rheumatoid arthritis - Clonal relationships and anti-citrulline autoantibody producing cells

A majority of circulating IgG is produced by plasma cells residing in the bone marrow (BM). Long-lived BM plasma cells constitute our humoral immune memory and are essential for infection-specific immunity. They may also provide a reservoir of potentially pathogenic autoantibodies, including rheumatoid arthritis (RA)-associated anti-citrullinated protein autoantibodies (ACPA). Here we investigated paired human BM plasma cell and peripheral blood (PB) B-cell repertoires in seropositive RA, four ACPA+ RA patients and one ACPA- using two different single-cell approaches, flow cytometry sorting, and transcriptomics, followed by recombinant antibody generation. Immunoglobulin (Ig) analysis of >900 paired heavy-light chains from BM plasma cells identified by either surface CD138 expression or transcriptome profiles (including gene expression of MZB1, JCHAIN and XBP1) demonstrated differences in IgG/A repertoires and N-linked glycosylation between patients. For three patients, we identified clonotypes shared between BM plasma cells and PB memory B cells. Notably, four individuals displayed plasma cells with identical heavy chains but different light chains, which may indicate receptor revision or clonal convergence. ACPA-producing BM plasma cells were identified in two ACPA+ patients. Three of 44 recombinantly expressed monoclonal antibodies from ACPA+ RA BM plasma cells were CCP2+, specifically binding to citrullinated peptides. Out of these, two clones reacted with citrullinated histone-4 and activated neutrophils. In conclusion, single-cell investigation of B-cell repertoires in RA bone marrow provided new understanding of human plasma cells clonal relationships and demonstrated pathogenically relevant disease-associated autoantibody expression in long-lived plasma cells.

Progression of pre-rheumatoid arthritis to clinical disease of joints: Potential role of mesenchymal stem cells

Rheumatoid arthritis (RA) related autoimmunity is developed at mucosal sites due to the interplay between genetic risk factors and environmental triggers. The pre-RA phase that leads to anti-citrullinated protein antibodies, rheumatoid factor, and other autoantibodies spread in the systemic circulation may not affect articular tissue for years until a mysterious second hit triggers the localization of RA-related autoimmunity in joints. Several players in the joint microenvironment mediate the synovial innate and adaptive immunological processes, eventually leading to clinical synovitis. There still exists a gap in the early phase of RA pathogenesis, i.e., the progression of diseases from the systemic circulation to joints. The lack of better understanding of these events results in the inability to answer questions about why only after a certain point of time the disease appears in joints and why in some cases, it simply remains latent and doesn't affect joints at all. In the current review, we focused on the immunomodulatory and regenerative role of mesenchymal stem cells and associated exosomes in RA pathology. We also highlighted the age-related dysregulations in activities of mesenchymal stem cells and how that might trigger homing of systemic autoimmunity to joints.

Predicting the onset of rheumatoid arthritis

Various scores have attempted to predict the onset of rheumatoid arthritis (RA). In particular, EULAR proposed a simple rule to identify new-onset arthralgia suspicious for progression to RA. However, its specificity would likely be higher if serological tests were included. In patients with clinical arthritis, reliable predictive criteria for progression to RA have also been identified. Overall, the validity of the available scores is still being debated. Such scores do not fully account for the interactions between risk factors in specific subpopulations. New technologies could help to overcome these limitations, but we need databases containing a sufficient number of RA and pre-RA patients, including pre-diagnostic monitoring. Today, the existing predictive rules cannot compete with expert opinions.

Diet and the risk of rheumatoid arthritis - A systematic literature review

OBJECTIVES

Diet has received attention as a factor possibly contributing to the development of Rheumatoid arthritis (RA). Several dietary exposures have been examined in various populations using different diet assessment methods. The aim of this study was to systematically assess the literature on the relation between dietary patterns, different food and food groups, macronutrients, non-alcoholic beverages and the risk of developing RA.

METHODS

A systematic literature search was performed to identify relevant articles on diet and the risk of developing RA. The selection of articles and overall quality assessment of all included studies were performed independently by two examiners. Overall study quality was evaluated using the Newcastle-Ottawa Scales. We excluded all articles where the temporal relation between dietary data collection and time of RA diagnosis was not presented. Main findings were summarized for cohort-based studies and case-control studies separately.

RESULTS

A total of 984 articles were screened. Nineteen relevant cohort-based studies, and eight case-control studies, were included in our review. Two articles were excluded due to lacking data on the relation between RA diagnosis and time of dietary data collection and one due to incorrect outcome. Identified studies suggested protective effects of fish, vegetables and Mediterranean-style diets, although study results and methods were heterogenous. An issue in some case-control studies was that unvalidated diet assessment methods were used. A vast majority of the cohort-based studies used validated diet assessment methods, although the definitions of exposures studied varied.

CONCLUSION

There is lack of consistent evidence on the role of diet in the development of RA, partly due to differences in study quality and methodology Limited evidence suggests that some healthy eating habits may reduce the risk of RA. More high-quality studies in the area are needed for a deeper understanding of the effect of diet, and to enable strategies to prevent RA.

The pathogenesis of rheumatoid arthritis

Significant recent progress in understanding rheumatoid arthritis (RA) pathogenesis has led to improved treatment and quality of life. The introduction of targeted-biologic and -synthetic disease modifying anti-rheumatic drugs (DMARDs) has also transformed clinical outcomes. Despite this, RA remains a life-long disease without a cure. Unmet needs include partial response and non-response to treatment in many patients, failure to achieve immune homeostasis or drug free remission, and inability to repair damaged tissues. RA is now recognized as the end of a multi-year prodromal phase in which systemic immune dysregulation, likely beginning in mucosal surfaces, is followed by a symptomatic clinical phase. Inflammation and immune reactivity are primarily localized to the synovium leading to pain and articular damage, but is also associated with a broader series of comorbidities. Here, we review recently described immunologic mechanisms that drive breach of tolerance, chronic synovitis, and remission.

Lifestyle Factors and Their Influence on Rheumatoid Arthritis: A Narrative Review

In recent years, a possible association of lifestyle factors with rheumatoid arthritis (RA) has attracted increasing public interest. The aim of this review is to provide an overview of the extent and the limitations of current evidence regarding lifestyle factors and RA. The PubMed medical database was screened for epidemiological and prospective studies investigating the contribution of lifestyle factors to the development and the course of the disease. Large epidemiological studies have identified smoking, unhealthy diet and adiposity, as well as a low educational level and low socioeconomic status, as factors that increase the incidence of RA. In addition, several lifestyle habits influence the response of RA to antirheumatic drugs. Among others, smoking, obesity and poor physical activity are associated with a worse treatment outcome. Methodological problems often impair firm conclusions with respect to the causal role of these factors in the risk and the course of RA. However, current evidence is sufficient to recommend a healthy diet, the prevention of obesity, the cessation of smoking and the maintenance of a high level of physical activity to support the effectivity of modern antirheumatic medication.

How does age determine the development of human immune-mediated arthritis?

Does age substantially affect the emergence of human immune-mediated arthritis? Children do not usually develop immune-mediated articular inflammation during their first year of life. In patients with juvenile idiopathic arthritis, this apparent ‘immune privilege’ disintegrates, and chronic inflammation is associated with variable autoantibody signatures and patterns of disease that resemble adult arthritis phenotypes. Numerous mechanisms might be involved in this shift, including genetic and epigenetic predisposing factors, maturation of the immune system with a progressive modulation of putative tolerogenic controls, parallel development of microbial dysbiosis, accumulation of a pro-inflammatory burden driven by environmental exposures (the exposome) and comorbidity-related drivers. By exploring these mechanisms, we expand the discussion of three (not mutually exclusive) hypotheses on how these factors can contribute to the differences and similarities between the loss of immune tolerance in children and the development of established immune-mediated arthritis in adults. These three hypotheses relate to a critical window in genetics and epigenetics, immune maturation, and the accumulation of burden. The varied manifestation of the underlying mechanisms among individuals is only beginning to be clarified, but the establishment of a framework can facilitate the development of an integrated understanding of the pathogenesis of arthritis across all ages.

In this Review, the authors discuss age-related arthropathy and the similarities and differences between childhood loss of immune tolerance and adult development of immune-mediated arthritis, and develop three hypotheses describing age-related mechanisms that contribute to the onset of arthritis.

The arthritis-free ‘immune privilege’ of early childhood is overridden by multiple mechanisms, progressively and age-dependently, generating recognizable patterns of chronic inflammatory arthritis.

The emergence of arthritis involves interconnected mechanisms related to immune priming, to a situational susceptibility and to the accumulation of an inflammatory burden.

The accumulation of epigenetic drift may contribute to differences across ages.

The exposome is expected to contribute to arthritis emergence in adults as well as in children.

Interplay of Environmental, Individual and Genetic Factors in Rheumatoid Arthritis Provocation

In this review, we explore systemization of knowledge about the triggering effects of non-genetic factors in pathogenic mechanisms that contribute to the development of rheumatoid arthritis (RA). Possible mechanisms involving environmental and individual factors in RA pathogenesis were analyzed, namely, infections, mental stress, sleep deprivation ecology, age, perinatal and gender factors, eating habits, obesity and smoking. The non-genetic factors modulate basic processes in the body with the impact of these factors being non-specific, but these common challenges may be decisive for advancement of the disease in the predisposed body at risk for RA. The provocation of this particular disease is associated with the presence of congenital loci minoris resistentia. The more frequent non-genetic factors form tangles of interdependent relationships and, thereby, several interdependent external factors hit one vulnerable basic process at once, either provoking or reinforcing each other. Understanding the specific mechanisms by which environmental and individual factors impact an individual under RA risk in the preclinical stages can contribute to early disease diagnosis and, if the factor is modifiable, might be useful for the prevention or delay of its development.

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

OBJECTIVE

Rheumatoid arthritis (RA) is more common in females, and although the cause of RA is unknown, it is characterized by the production of autoantibodies. The aims of this study were to determine whether RA-associated autoantibodies are more often found in females than males and to identify factors that influence the relationship between sex and seropositivity.

METHODS

Databases were searched and studies of RA (N ≥ 100) were included if they reported proportion of seropositive patients with RA by sex. Metaanalyses and metaregression were conducted using the random-effects model. Covariates regressed were smoking, age, BMI, Health Assessment Questionnaire-Disability Index (HAQ-DI), and the Disease Activity Score in 28 joints (DAS28).

RESULTS

Eighty-four studies with a total of 141,381 subjects with rheumatoid factor (RF) seropositivity and 95,749 subjects with anticitrullinated protein antibody (ACPA) seropositivity met inclusion criteria. The mean age of participants ranged from 37 to 68 years and the proportion of female subjects ranged from 9% to 92%. Results indicated that females were less likely than males to be seropositive: odds ratio (OR) 0.84 [95% CI 0.77-0.91] for RF and OR 0.88 [95% CI 0.81-0.95] for ACPA. BMI, smoking, mean age, DAS28, and HAQ-DI did not affect the relationship between sex and seropositivity.

CONCLUSION

Although studies report that females have higher RA disease activity than males and that seropositivity predicts worse outcomes, females were less likely to be seropositive than males.

Preclinical Autoimmune Disease: a Comparison of Rheumatoid Arthritis, Systemic Lupus Erythematosus, Multiple Sclerosis and Type 1 Diabetes

The preclinical phase of autoimmune disorders is characterized by an initial asymptomatic phase of varying length followed by nonspecific signs and symptoms. A variety of autoimmune and inflammatory manifestations can be present and tend to increase in the last months to years before a clinical diagnosis can be made. The phenotype of an autoimmune disease depends on the involved organs, the underlying genetic susceptibility and pathophysiological processes. There are different as well as shared genetic or environmental risk factors and pathophysiological mechanisms between separate diseases. To shed more light on this, in this narrative review we compare the preclinical disease course of four important autoimmune diseases with distinct phenotypes: rheumatoid arthritis (RA), Systemic Lupus Erythematosus (SLE), multiple sclerosis (MS) and type 1 diabetes (T1D). In general, we observed some notable similarities such as a North-South gradient of decreasing prevalence, a female preponderance (except for T1D), major genetic risk factors at the HLA level, partly overlapping cytokine profiles and lifestyle risk factors such as obesity, smoking and stress. The latter risk factors are known to produce a state of chronic systemic low grade inflammation. A central characteristic of all four diseases is an on average lengthy prodromal phase with no or minor symptoms which can last many years, suggesting a gradually evolving interaction between the genetic profile and the environment. Part of the abnormalities may be present in unaffected family members, and autoimmune diseases can also cluster in families. In conclusion, a promising strategy for prevention of autoimmune diseases might be to address adverse life style factors by public health measures at the population level.

A Roadmap for Investigating Preclinical Autoimmunity Using Patient-Oriented and Epidemiologic Study Designs: Example of Rheumatoid Arthritis

Background & Aims

Rheumatoid arthritis (RA) is a prototypic autoimmune disease causing inflammatory polyarthritis that affects nearly 1% of the population. RA can lead to joint destruction and disability along with increased morbidity and mortality. Similar to other autoimmune diseases, RA has distinct preclinical phases corresponding to genetic risk, lifestyle risk factors, autoantibody development, and non-specific symptoms prior to clinical diagnosis. This narrative review will detail observational studies for RA risk and clinical trials for RA prevention as a roadmap to investigating preclinical autoimmunity that could be applied to other diseases.

Methods

In this narrative review, we summarized previous and ongoing research studies investigating RA risk and prevention, categorizing them related to their design and preclinical phases.

Results

We detailed the following types of studies investigating RA risk and prevention: retrospective population-based and administrative datasets; prospective studies (case-control and cohort; some enrolling based on genetics, first-degree relative status, elevated biomarkers, or early symptoms/arthritis); and randomized clinical trials. These correspond to all preclinical RA phases (genetic, lifestyle, autoimmunity, early signs/symptoms). Previous and ongoing randomized controlled trials have enrolled individuals at very elevated risk for RA based on biomarkers, symptoms, imaging abnormalities, or early signs/symptoms.

Conclusion

We detailed the rich variety of study designs that is necessary to investigate distinct preclinical phases of an autoimmune disease such as RA. However, further progress is needed to fully elucidate the pathogenesis of RA that may ultimately lead to prevention or delay of disease onset.

Potential Cancer Risk in Patients with Rheumatoid Arthritis: A Longitudinal Korean Population-Based Analysis

The potential link between rheumatoid arthritis (RA) and cancer incidence needs to be validated due to inconsistent results between Asian and Western countries. We explored the long-term association of RA with the overall and organ-specific cancer incidence using nationwide population data. This longitudinal follow-up study (2002–2015) included 3070 patients with RA and 12,280 controls (1:4 propensity score-matched for sex, age, residence, and income) from the Korean National Health Insurance Service-Health Screening Cohort database. A Cox proportional hazard model estimated the hazard ratio for malignancy following adjusting for covariates. Despite the similar overall cancer incidence between RA and control groups, differences in the incidence of organ-specific cancers were noted: the RA group had a 1.63-fold greater likelihood for lung cancer (95% confidence interval 1.11–2.40). In the sex-stratified subgroup analyses, the male RA patients exhibited higher odds of lung and thyroid cancer but a lower probability for colorectal cancer; no such associations were detected in either female patients with RA or age subgroups. In summary, the higher likelihood for lung cancer in Korean RA patients, especially thyroid and lung cancer in male RA patients, seems to be characteristic, which needs to be carefully monitored.

A Role of IL-17 in Rheumatoid Arthritis Patients Complicated With Atherosclerosis

Rheumatoid arthritis (RA) is mainly caused by joint inflammation. RA significantly increases the probability of cardiovascular disease. Although the progress of RA has been well controlled recently, the mortality of patients with RA complicated with cardiovascular disease is 1.5–3 times higher than that of patients with RA alone. The number of people with atherosclerosis in patients with RA is much higher than that in the general population, and atherosclerotic lesions develop more rapidly in patients with RA, which has become one of the primary factors resulting in the death of patients with RA. The rapid development of atherosclerosis in RA is induced by inflammation-related factors. Recent studies have reported that the expression of IL-17 is significantly upregulated in patients with RA and atherosclerosis. Simultaneously, there is evidence that IL-17 can regulate the proliferation, migration, and apoptosis of vascular endothelial cells and vascular smooth muscle cells through various ways and promote the secretion of several cytokines leading to the occurrence and development of atherosclerosis. Presently, there is no clear prevention or treatment plan for atherosclerosis in patients with RA. Therefore, this paper explores the mechanism of IL-17 in RA complicated with atherosclerosis and shows the reasons for the high incidence of atherosclerosis in patients with RA. It is hoped that the occurrence and development of atherosclerosis in patients with RA can be diagnosed or prevented in time in the early stage of lesions, and the prevention and treatment of cardiovascular complications in patients with RA can be enhanced to reduce mortality.

Genetics of rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease involving symmetric joints and is generally characterized by persistent pain, tenderness, and destruction of joints. The vast majority of RA patients produce autoantibodies, and immune cell involvement in disease development is well recognized, as is the contribution of other types of cells in synovial tissue, like fibroblasts. It is known that there are major genetic associations with the HLA locus, while multiple non-HLA genetic variants display relatively low risk of RA. Both HLA and non-HLA associations suggest that the profiles of genetic associations for autoantibody-positive vs. autoantibody-negative RA are different. Several alleles of HLA-DRB1 are associated with high risk for autoantibody-positive RA, with the strongest risk characterized by valine at position 11 of the protein sequence (HLA-DRB1*04 and *10 alleles). There is a strong protective effect for the risk of autoantibody-positive RA associated with HLA-DRB1*13 alleles. Although major genetic associations have been known for several years, understanding of the specific mechanisms in the development of increased risk of RA for these variations is work in progress. Current studies focus on the binding of immune receptors involved in recognition of putative peptides in activation of T cells, as well as investigation of cell signaling mechanisms. At least a part of RA risk could be explained by gene-gene and gene-environment interactions. There are currently more than 150 candidate loci with polymorphisms that associate with RA, mainly related to seropositive disease, and new discoveries are anticipated in the future from investigation of diverse human populations. This new research will help create a strong foundation for the continuing process of integrating genetic, epigenetic, transcriptomic, and proteomic data in studies of RA.

Systematic Evaluation of Rheumatoid Arthritis Risk by Integrating Lifestyle Factors and Genetic Risk Scores

Background

Effective identification of high-risk rheumatoid arthritis (RA) individuals is still a challenge. Whether the combined effects of multiple previously reported genetic loci together with lifestyle factors can improve the prediction of RA risk remains unclear.

Methods

Based on previously reported results and a large-scale Biobank dataset, we constructed a polygenic risk score (PRS) for RA to evaluate the combined effects of the previously identified genetic loci in both case-control and prospective cohorts. We then evaluated the relationships between several lifestyles and RA risk and determined healthy lifestyles. Then, the joint effects of healthy lifestyles and genetic risk on RA risk were evaluated.

Results

We found a positive association between PRS and RA risk (OR = 1.407, 95% confidence interval (CI) = 1.354~1.463; HR = 1.316, 95% CI = 1.257~1.377). Compared with the low genetic risk group, the group with intermediate or high genetic risk had a higher risk (OR = 1.347, 95% CI = 1.213~1.496; HR = 1.246, 95% CI = 1.108~1.400) (OR = 2.169, 95% CI = 1.946~2.417; HR = 1.762, 95% CI = 1.557~1.995). After adjusting for covariates, we found protective effects of three lifestyles (no current smoking, regular physical activity, and moderate body mass index) on RA risk and defined them as healthy lifestyles. Compared with the individuals with low genetic risks and favorable lifestyles, those with high genetic risks and unfavorable lifestyles had as high as OR of 4.637 (95%CI = 3.767~5.708) and HR of 3.532 (95%CI = 2.799~4.458).

Conclusions

In conclusion, the integration of PRS and lifestyles can improve the prediction of RA risk. High RA risk can be alleviated by adopting healthy lifestyles but aggravated by adopting unfavorable lifestyles.

Cigarette smoking and risk of palindromic rheumatism: A propensity score matching analysis

Present study was conducted to investigate smoking status in palindromic rheumatism (PR) patients compared to healthy individuals as well as to assess the effect of smoking on clinical features and outcomes of PR. One hundred and forty-six patients with diagnosis of PR and 346 healthy controls were included in this study. Demographic, clinical, and laboratory characteristics and the smoking history of PR patients at the cohort entry were obtained from patients' records. Demographic and smoking history of the control group were obtained by direct interview. In order to reduce heterogeneity between the studied groups, propensity score matching (PSM) analyses was performed. Matching was achieved by considering age, gender, educational status, and marital status. After PSM, we carried out a multivariate analysis with PR as the main outcome variable, ever smoking as the main predictor variable and age, gender, educational status, and marital status as covariates. PSM resulted in 123 PR patients and 246 matched controls. Multivariate analysis did not show a significant increase in the risk of PR in ever smokers. Seventy-six patients were anti-citrullinated protein/peptide antibody positive (ACPA-positive). Multivariate logistic regression showed a significant increase in the risk of PR in ACPA-positive ever smokers. Except lower sustained remission rate in ever smokers, no significant differences were observed in clinical manifestations and outcomes of PR between ever and never smokers. In conclusion, smoking is a risk factor for ACPA-positive PR.

Management of Rheumatoid Arthritis: An Overview

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease of unknown etiology, primarily affecting the joints, then extra-articular manifestations can occur. Due to its complexity, which is based on an incompletely elucidated pathophysiological mechanism, good RA management requires a multidisciplinary approach. The clinical status of RA patients has improved in recent years due to medical advances in diagnosis and treatment, that have made it possible to reduce disease activity and prevent systemic complications. The most promising results were obtained by developing disease-modifying anti-rheumatic drugs (DMARDs), the class to which conventional synthetic, biologic, and targeted synthetic drugs belong. Furthermore, ongoing drug development has led to obtaining molecules with improved efficacy and safety profiles, but further research is needed until RA turns into a curable pathology. In the present work, we offer a comprehensive perspective on the management of RA, by centralizing the existing data provided by significant literature, emphasizing the importance of an early and accurate diagnosis associated with optimal personalized treatment in order to achieve better outcomes for RA patients. In addition, this study suggests future research perspectives in the treatment of RA that could lead to higher efficacy and safety profiles and lower financial costs.

Four Systemic Lupus Erythematosus Subgroups, Defined by Autoantibodies Status, Differ Regarding HLA-DRB1 Genotype Associations and Immunological and Clinical Manifestations

Objective

The heterogeneity of systemic lupus erythematosus (SLE) constitutes clinical and therapeutical challenges. We therefore studied whether unrecognized disease subgroups can be identified by using autoantibody profiling together with HLA‐DRB1 alleles and immunological and clinical data.

Methods

An unsupervised cluster analysis was performed based on detection of 13 SLE‐associated autoantibodies (double‐stranded DNA, nucleosomes, ribosomal P, ribonucleoprotein [RNP] 68, RNPA, Smith [Sm], Sm/RNP, Sjögren's syndrome antigen A [SSA]/Ro52, SSA/Ro60, Sjögren's syndrome antigen B [SSB]/La, cardiolipin [CL]‐Immunoglobulin G [IgG], CL–Immunoglobulin M [IgM], and β₂ glycoprotein I [β₂GPI]–IgG) in 911 patients with SLE from two cohorts. We evaluated whether each SLE subgroup is associated with HLA‐DRB1 alleles, clinical manifestations (n = 743), and cytokine levels in circulation (n = 446).

Results

Our analysis identified four subgroups among the patients with SLE. Subgroup 1 (29.3%) was dominated by anti‐SSA/Ro60/Ro52/SSB autoantibodies and was strongly associated with HLA‐DRB1*03 (odds ratio [OR] = 4.73; 95% confidence interval [CI] = 4.52‐4.94). Discoid lesions were more common for this disease subgroup (OR = 1.71, 95% CI = 1.18‐2.47). Subgroup 2 (28.7%) was dominated by anti‐nucleosome/SmRNP/DNA/RNPA autoantibodies and associated with HLA‐DRB1*15 (OR = 1.62, 95% CI = 1.41‐1.84). Nephritis was most common in this subgroup (OR = 1.61, 95% CI = 1.14‐2.26). Subgroup 3 (23.8%) was characterized by anti‐ß₂GPI‐IgG/anti‐CL–IgG/IgM autoantibodies and a higher frequency of HLA‐DRB1*04 compared with the other patients with SLE. Vascular events were more common in Subgroup 3 (OR = 1.74, 95% CI = 1.2‐2.5). Subgroup 4 (18.2%) was negative for the investigated autoantibodies, and this subgroup was not associated with HLA‐DRB1. Additionally, the levels of eight cytokines significantly differed among the disease subgroups.

Conclusion

Our findings suggest that four fairly distinct subgroups can be identified on the basis of the autoantibody profile in SLE. These four SLE subgroups differ regarding associations with HLA‐DRB1 alleles and immunological and clinical features, suggesting dissimilar disease pathways.

Cohort profile: SCREEN-RA: design, methods and perspectives of a Swiss cohort study of first-degree relatives of patients with rheumatoid arthritis

PURPOSE

Rheumatoid arthritis (RA) is an insidious autoimmune disease, with an immunological onset years before diagnosis. Early interventions in preclinical stages could prevent or minimise the progression towards irreversible joint damage. The SCREEN-RA cohort (Evaluation of a SCREENing strategy for Rheumatoid Arthritis) aims to characterise the preclinical stages of the disease, to identify environmental risk factors, and to discover or validate novel biomarkers predictive for RA development.

PARTICIPANTS

SCREEN-RA includes an at-risk population for RA, namely first-degree relatives of patients with established RA.

FINDINGS TO DATE

The cohort started in 2009 is composed of mostly asymptomatic healthy individuals (total n=1458, 7262 person-years), with a mean age of 44 years at enrolment, 74% female and 91% Caucasian ethnicity. During the study period, 16 participants have developed RA. All participants provide baseline serum, DNA and RNA samples, and in a subset, stool samples and oral examination are performed for microbiota assessment. At enrolment, 10% of participants had asymptomatic autoimmunity associated with RA (n=147), 10% presented 'clinically suspect arthralgias' (n=143) and 3% reported arthralgias in conjunction with autoimmunity or high genetic risk (n=51). Studies with this cohort have uncovered risk factors for RA development, such as female hormonal factors, poor oral health or intestinal dysbiosis.

FUTURE PLANS

Future directions include immunological and 'multiomics' approaches to discover new biological markers of progression towards RA, as well as testing preventive interventions in 'high-risk' population.

Association between number and type of different ACPA fine specificities with lung abnormalities in early, untreated rheumatoid arthritis

Background

Rheumatoid arthritis (RA)-associated anticitrullinated protein/peptide antibodies (ACPA) might originate at mucosal sites such as the lungs. We aimed to examine the relationship between the ACPA repertoire and lung abnormalities on high-resolution CT (HRCT) in patients with earlyuntreated RA.

Methods

106 patients with newly diagnosed untreated RA were examined with HRCT of the lungs. Blood samples were analysed for presence of rheumatoid factor (RF) and ACPA using either a CCP2 detection kit or an immunochip containing 10 different citrullinated peptides. Association between HRCT findings and the antibody repertoire was assessed by logistic regression analysis.

Results

The number (%) of patients with HRCT abnormalities was 58 (54.7%) for parenchymal abnormalities and 68 (64.2%) for airway abnormalities. CCP2 IgG, RF IgA and antibodies against citrullinated fibrinogen were associated with the presence of parenchymal lung abnormalities. Interestingly, a high number of ACPA fine specificities gave a high risk of having parenchymal lung abnormalities at the time of RA diagnosis. No significant signals were identified between ACPA specificities and risk for airway abnormalities.

Conclusions

The presence of RF and ACPAs (especially against citrullinated fibrinogen peptides) as well as high number of ACPAs fine specificities are associated with parenchymal lung abnormalities in patients with early, untreated RA. This provides further support for an important pathogenic link between the lung and systemic autoimmunity, contributing to RA development.

A double-blind placebo-controlled randomized trial of oral saffron in the treatment of rheumatoid arthritis

OBJECTIVE

Recently, saffron (Crocus sativus L. from the Iridaceae family) has been characterized by its antioxidant, anti-inflammatory and analgesic effects. This study aimed to evaluate the effect of saffron on disease activity in patients with rheumatoid arthritis (RA).

MATERIALS AND METHODS

This is a double-blind, placebo-controlled, randomized clinical trial (RCT) performed on 55 newly- diagnosed RA patients without previous treatment, who were randomly divided into intervention (included 28 cases) and control groups (consisted of 27 individuals). Standard therapy including prednisolone, oral methotrexate, folic acid, vitamin D, calcium, and alendronate, was administered similarly in both groups. Patients received a 100 mg saffron pill/day (pure saffron powder) or placebo besides the standard protocol. The placebo had the same shape as the saffron pills. Follow up of DAS28ESR disease activity score was done on the 30th, 45th and 90th day of the study.

RESULTS

There was no difference between the intervention and control groups regarding to the DAS28ESR at the end of the study. However, a significant decrease in DAS28-ESR was observed in each group compared to the first visit (p=0.001). The results also showed no significant difference in the incidence of side effects in both groups.

CONCLUSION

In summary, patients who received pure saffron pills (100 mg/day) in addition to standard therapy did not have a significant difference in improvement of disease activity from the patients on standard therapy.

Challenges and Opportunities of Targeted Behavioral Interventions for Groups at Risk for Developing Rheumatoid Arthritis

Background: Rheumatoid arthritis (RA) is a serious autoimmune disease which causes painful, swollen joints and can impact quality of life and increase morbidity and mortality. There are several preclinical stages of RA that correspond to at-risk groups that include: genetic risk, risk from behaviors, elevation of RA-related autoantibodies, and early clinical disease manifestations such as undifferentiated arthritis. Early interventions are crucial to slowing progression to and potentially preventing RA onset. Modification of behaviors among at-risk individuals may decrease RA risk. There are several challenges and opportunities in implementing preventative behavioral interventions, which may vary within different at-risk groups. Methods: We performed a narrative review of the literature, including meta-analyses focused on RA risk-related behaviors as well as publications investigating the potential efficacy of behavioral modifications on RA risk. Results: There are multiple behavioral risk factors associated with RA, including smoking, obesity, low physical activity, low quality diet, and poor dental hygiene, which may contribute to progression to clinical RA. Meta-analyses have been performed for smoking, excess body weight, and physical activity. Likelihood of adopting behavioral modifications may increase as RA risk increases. Conclusions: Clinicians may be able to tailor preventative approaches to various RA at-risk groups to help reduce RA risk, but further research is needed. A better understanding of the relationship of behaviors with RA risk and optimized approaches to implementing behavioral changes may allow for clinicians to tailor their preventative approaches for at-risk individuals.

A Comprehensive Evaluation of the Relationship Between Different IgG and IgA Anti-Modified Protein Autoantibodies in Rheumatoid Arthritis

Seropositive rheumatoid arthritis (RA) is characterized by the presence of rheumatoid factor (RF) and anti-citrullinated protein autoantibodies (ACPA) with different fine-specificities. Yet, other serum anti-modified protein autoantibodies (AMPA), e.g. anti-carbamylated (Carb), -acetylated (KAc), and malondialdehyde acetaldehyde (MAA) modified protein antibodies, have been described. In this comprehensive study, we analyze 30 different IgG and IgA AMPA reactivities to Cit, Carb, KAc, and MAA antigens detected by ELISA and autoantigen arrays in N=1985 newly diagnosed RA patients. Association with patient characteristics such as smoking and disease activity were explored. Carb and KAc reactivities by different assays were primarily seen in patients also positive for anti-citrulline reactivity. Modified vimentin (mod-Vim) peptides were used for direct comparison of different AMPA reactivities, revealing that IgA AMPA recognizing mod-Vim was mainly detected in subsets of patients with high IgG anti-Cit-Vim levels and a history of smoking. IgG reactivity to acetylation was mainly detected in a subset of patients with Cit and Carb reactivity. Anti-acetylated histone reactivity was RA-specific and associated with high anti-CCP2 IgG levels, multiple ACPA fine-specificities, and smoking status. This reactivity was also found to be present in CCP2+ RA-risk individuals without arthritis. Our data further demonstrate that IgG autoreactivity to MAA was increased in RA compared to controls with highest levels in CCP2+ RA, but was not RA-specific, and showed low correlation with other AMPA. Anti-MAA was instead associated with disease activity and was not significantly increased in CCP2+ individuals at risk of RA. Notably, RA patients could be subdivided into four different subsets based on their AMPA IgG and IgA reactivity profiles. Our serology results were complemented by screening of monoclonal antibodies derived from single B cells from RA patients for the same antigens as the RA cohort. Certain CCP2+ clones had Carb or Carb+KAc+ multireactivity, while such reactivities were not found in CCP2- clones. We conclude that autoantibodies exhibiting different patterns of ACPA fine-specificities as well as Carb and KAc reactivity are present in RA and may be derived from multireactive B-cell clones. Carb and KAc could be considered reactivities within the “Cit-umbrella” similar to ACPA fine-specificities, while MAA reactivity is distinctly different.

Biomarkers in Rheumatoid Arthritis

The utilization and identification of biomarkers in rheumatoid arthritis (RA) to facilitate timely diagnosis and the optimal management of the disease is an area of active investigation. This review focuses on biomarkers available for routine clinical use, details potential investigational biomarkers, and raises outstanding clinical questions.

Elevated Anti-Citrullinated Protein Antibodies Prior to Rheumatoid Arthritis Diagnosis and Risks for Chronic Obstructive Pulmonary Disease or Asthma

OBJECTIVE

To investigate elevation of anti-citrullinated protein antibodies (ACPAs) before diagnosis of rheumatoid arthritis (RA) and risks for chronic obstructive pulmonary disease (COPD) or asthma.

METHODS

We performed a matched cohort study nested within the Nurses' Health Studies among women who donated blood. Women with incident RA after blood draw (self-reported, then confirmed by medical records) were each matched to 3 controls by age, cohort, year, and menopausal factors. Pre-RA ACPA positivity was defined as >99th percentile of control distribution by a research assay or by cyclic citrullinated peptide in a subset. Incident COPD and asthma after index date (date of blood draw) were identified by questionnaires. Cox regression estimated hazard ratios (HRs) for incident COPD or asthma (in separate analyses) associated with pre-RA, pre-RA ACPA+, or pre-RA ACPA- phenotypes each compared to their matched non-RA controls.

RESULTS

We analyzed 283 women who were pre-RA and 842 controls; blood was donated a mean ± SD of 9.7 ± 5.8 years before RA diagnosis. Fifty-nine women (20.8%) were pre-RA ACPA+. There were 107 cases of incident COPD and 105 incident asthma cases during 21,489 person-years of follow-up. Pre-RA ACPA+ was associated with increased COPD risk (HR 3.04 [95% confidence interval (95% CI) 1.33-7.00]) after adjusting for covariates including smoking pack-years. Pre-RA ACPA+ had an HR for asthma of 1.74 (multivariable 95% CI 0.72-4.24), similar to the risk of asthma for pre-RA ACPA- (HR 1.65 [95% CI 1.11-2.46]).

CONCLUSION

Women with elevated ACPA before RA diagnosis had increased risk for developing COPD compared to controls. Women who later developed RA were more likely to develop asthma than controls, regardless of pre-RA ACPA status.

Meta-analysis of genome-wide DNA methylation identifies shared associations across neurodegenerative disorders

BACKGROUND

People with neurodegenerative disorders show diverse clinical syndromes, genetic heterogeneity, and distinct brain pathological changes, but studies report overlap between these features. DNA methylation (DNAm) provides a way to explore this overlap and heterogeneity as it is determined by the combined effects of genetic variation and the environment. In this study, we aim to identify shared blood DNAm differences between controls and people with Alzheimer's disease, amyotrophic lateral sclerosis, and Parkinson's disease.

RESULTS

We use a mixed-linear model method (MOMENT) that accounts for the effect of (un)known confounders, to test for the association of each DNAm site with each disorder. While only three probes are found to be genome-wide significant in each MOMENT association analysis of amyotrophic lateral sclerosis and Parkinson's disease (and none with Alzheimer's disease), a fixed-effects meta-analysis of the three disorders results in 12 genome-wide significant differentially methylated positions. Predicted immune cell-type proportions are disrupted across all neurodegenerative disorders. Protein inflammatory markers are correlated with profile sum-scores derived from disease-associated immune cell-type proportions in a healthy aging cohort. In contrast, they are not correlated with MOMENT DNAm-derived profile sum-scores, calculated using effect sizes of the 12 differentially methylated positions as weights.

CONCLUSIONS

We identify shared differentially methylated positions in whole blood between neurodegenerative disorders that point to shared pathogenic mechanisms. These shared differentially methylated positions may reflect causes or consequences of disease, but they are unlikely to reflect cell-type proportion differences.

Interaction between the STAT4 rs11889341(T) risk allele and smoking confers increased risk of myocardial infarction and nephritis in patients with systemic lupus erythematosus

Objective

To investigate how genetics influence the risk of smoking-related systemic lupus erythematosus (SLE) manifestations.

Methods

Patients with SLE (n_{discovery cohort}=776, n_{replication cohort}=836) were genotyped using the 200K Immunochip single nucleotide polymorphisms (SNP) Array (Illumina) and a custom array. Sixty SNPs with SLE association (p<5.0×10⁻⁸) were analysed. Signal transducer and activator of transcription 4 (STAT4) activation was assessed in in vitro stimulated peripheral blood mononuclear cells from healthy controls (n=45).

Results

In the discovery cohort, smoking was associated with myocardial infarction (MI) (OR 1.96 (95% CI 1.09 to 3.55)), with a greater effect in patients carrying any rs11889341 STAT4 risk allele (OR 2.72 (95% CI 1.24 to 6.00)) or two risk alleles (OR 8.27 (95% CI 1.48 to 46.27)).

Smokers carrying the risk allele also displayed an increased risk of nephritis (OR 1.47 (95% CI 1.06 to 2.03)). In the replication cohort, the high risk of MI in smokers carrying the risk allele and the association between the STAT4 risk allele and nephritis in smokers were confirmed (OR 6.19 (95% CI 1.29 to 29.79) and 1.84 (95% CI 1.05 to 3.29), respectively).

The interaction between smoking and the STAT4 risk allele resulted in further increase in the risk of MI (OR 2.14 (95% CI 1.01 to 4.62)) and nephritis (OR 1.53 (95% CI 1.08 to 2.17)), with 54% (MI) and 34% (nephritis) of the risk attributable to the interaction. Levels of interleukin-12-induced phosphorylation of STAT4 in CD8+ T cells were higher in smokers than in non-smokers (mean geometric fluorescence intensity 1063 vs 565, p=0.0063).

Lastly, the IL12A rs564799 risk allele displayed association with MI in both cohorts (OR 1.53 (95% CI 1.01 to 2.31) and 2.15 (95% CI 1.08 to 4.26), respectively).

Conclusions

Smoking in the presence of the STAT4 risk gene variant appears to increase the risk of MI and nephritis in SLE. Our results also highlight the role of the IL12−STAT4 pathway in SLE-cardiovascular morbidity.

The pre-clinical phase of rheumatoid arthritis: From risk factors to prevention of arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease considered as a multistep process spanning from the interaction of genetic (e.g., shared epitope or non-HLA loci), environmental and behavioral risk factors (e.g., smoking) leading to breaking immune tolerance and autoimmune processes such as the production of autoantibodies (e.g., antibodies against citrullinated proteins ACPA or rheumatoid factors, RF), development of the first symptoms without clinical arthritis, and, finally, the manifestation of arthritis. Despite the typical joint involvement in established RA, the pathogenesis of the disease likely begins far from joint structures: in the lungs or periodontium in association with citrullination, intestinal microbiome, or adipose tissue, which supports normal findings in synovial tissue in ACPA+ patients with arthralgia. The presence of ACPA is detectable even years before the first manifestation of RA. The pre-clinical phase of RA is the period preceding clinically apparent RA with ACPA contributing to the symptoms without subclinical inflammation. While the combination of ACPA and RF increases the risk of progression to RA by up to 10 times, increasing numbers of novel autoantibodies are to be investigated to contribute to the increased risk and pathogenesis of RA. With growing knowledge about the course of RA, new aspiration emerges to cure and even prevent RA, shifting the "window of opportunity" to the pre-clinical phases of RA. The clinical definition of individuals at risk of developing RA (clinically suspect arthralgia, CSA) makes it possible to unify these at-risk individuals' clinical characteristics for "preventive" treatment in ongoing clinical trials using mostly biological or conventional synthetic disease-modifying drugs. However, the combination of symptoms, laboratory, and imaging biomarkers may be the best approach to select the correct target at-risk population. The current review aims to explore different phases of RA and discuss the potential of (non)pharmacological intervention aiming to prevent RA.

Systematic Review and Meta-analysis on the Association of Occupational Exposure to Free Crystalline Silica and Rheumatoid Arthritis

• Occupational exposure to free crystalline silica and tobacco smoking are associated with an increased risk rheumatoid arthritis, with the evidence of an interaction in seropositive subjects.

• Further studies in the field are needed to support such association

We carried out a systematic search for all published epidemiological studies concerning the association between occupational exposure to free crystalline silica (FCS) and subsequent development of rheumatoid arthritis (RA). A meta-analysis was conducted on relevant studies. We searched PubMed and Embase, search engines, for original articles published (from 1960 to November 2019) in any language. In addition, we also searched reference lists of included studies manually for additional relevant articles. Finally, twelve studies were included in the meta-analysis (seven case-control cases and five cohort studies). The odds risks and 95% confidence interval (CI) were calculated using a random effect meta-analysis. A primary meta-analysis (using a random effect model)—regarding RA risk in subjects exposed to FCS—yelled to an overall OR of 1.94 (95% CI 1.46–2.58). We also conducted three further meta-analysis, taking into account the presence of autoantibodies (anti-RF or anti-ACPA) and smoking habits and found a significant association between FCS and RA in both seropositive and seronegative subjects (OR 1.74, 95% CI 1.35–2.25 and OR 1.23, 95% CI 1.06–1.4, respectively) and in seropositive subjects which were smokers (OR 3.30, 95% CI 2.40–4.54). The studies that have investigated the association between RA and occupatational exposure to FCS are still scarce and the heterogeneity between the studies remains high. Some critical limitations have been identified within studies, among which, the methods for assessing exposure stand out. Although with due caution, our results confirm the hypothesis of an association between occupational exposure to FCS and RA development. There was an interaction between FCS and tobacco smoking in RA seropositive workers.

Citrullinated inter-alpha-trypsin inhibitor heavy chain 4 in arthritic joints and its potential effect in the neutrophil migration

The citrullinated inter-alpha-trypsin inhibitor heavy chain 4 (cit-ITIH4) was identified as its blood level was associated with the arthritis score in peptide glucose-6-phosphate-isomerase-induced arthritis (pGIA) mice and the disease activity in patients with rheumatoid arthritis (RA). This study aimed to clarify its citrullination pathway and function as related to neutrophils. In pGIA-afflicted joints, ITIH4 and cit-ITIH4 levels were examined by immunohistochemistry (IHC), immunoprecipitation (IP) and Western blotting (WB), while peptidylarginine deiminase (PAD) expression was measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), IHC and immunofluorescent methods. The pGIA mice received anti-lymphocyte antigen 6 complex locus G6D (Ly6G) antibodies to deplete neutrophils and the expression of cit-ITIH4 was investigated by WB. The amounts of ITIH4 and cit-ITIH4 in synovial fluid (SF) from RA and osteoarthritis (OA) patients were examined by I.P. and W.B. Recombinant ITIH4 and cit-ITIH4 were incubated with sera from healthy volunteers before its chemotactic ability and C5a level were evaluated using Boyden's chamber assay and enzyme-linked immunosorbent assay (ELISA). During peak arthritic phase, ITIH4 and cit-ITIH4 were increased in joints while PAD4 was over-expressed, especially in the infiltrating neutrophils of pGIA mice. Levels of cit-ITIH4 in plasma and joints significantly decreased upon neutrophil depletion. ITIH4 was specifically citrullinated in SF from RA patients compared with OA patients. Native ITIH4 inhibited neutrophilic migration and decreased C5a levels, while cit-ITIH4 increased its migration and C5a levels significantly. Cit-ITIH4 is generated mainly in inflamed joints by neutrophils via PAD4. Citrullination of ITIH4 may change its function to up-regulate neutrophilic migration by activating the complement cascade, exacerbating arthritis.

Association of Agricultural, Occupational, and Military Inhalants With Autoantibodies and Disease Features in US Veterans With Rheumatoid Arthritis

OBJECTIVE

To determine the association of inhalant exposures with rheumatoid arthritis (RA)-related autoantibodies and severity in US veterans.

METHODS

Participants in the Veterans Affairs Rheumatoid Arthritis (VARA) registry were mailed surveys assessing occupational, agricultural, and military inhalant exposures. Demographic characteristics, disease activity, functional status, and extraarticular features were obtained from the VARA registry, while HLA-DRB1 shared epitope (SE) status, anti-cyclic citrullinated peptide (anti-CCP) antibodies, and rheumatoid factor (RF) were measured using banked DNA/serum from enrollment. Associations between inhalant exposures and RA-related factors (autoantibodies, severity, and extraarticular features) were assessed using multivariable linear and logistic regression models adjusted for age, sex, race, and tobacco use and stratified by SE status. Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

Questionnaires were returned by 797 of 1,566 participants (50.9%). Survey respondents were older, more often White or male, and less frequently smokers, and had lower disease activity compared to nonrespondents. Anti-CCP positivity was more common among veterans exposed to burn pits (OR 1.66 [95% CI 1.02, 2.69]) and military waste disposal (OR 1.74 [95% CI 1.04, 2.93]) independent of other factors. Among participants who were positive for SE alleles, burn pit exposure (OR 5.69 [95% CI 2.73, 11.87]) and military waste disposal exposure (OR 5.05 [95% CI 2.42, 10.54]) were numerically more strongly associated with anti-CCP positivity. Several inhalant exposures were associated with the presence of chronic lung disease, but not with the presence of RF or the level of disease activity.

CONCLUSION

Military burn pit exposure and military waste disposal exposure were independently associated with the presence of anti-CCP antibodies in RA patients. These findings are consistent with emerging evidence that various inhalant exposures influence autoantibody expression and RA risk.

Etiologies of Rheumatoid Arthritis: Update on Mucosal, Genetic, and Cellular Pathogenesis

Purpose of Review

Over the last few years, the scientific community has made significant progress in understanding the etiology of rheumatoid arthritis (RA). In this review, we summarize those key findings and trends.

Recent Findings

New data strongly implicates respiratory exposures, obesity, diet and microbiome, genetics, and their interactions in the etiology of RA. Furthermore, anti-posttranslationally modified protein antibodies (AMPAs) and abnormal glycosylation may be additional biomarkers for RA. Finally, functional genomics techniques implicate loss of certain macrophage populations and proliferation of synovial fibroblasts in RA.

Summary

These findings support the notion that RA originates at mucosal sites, augmented by genetic predisposition, and mediated by certain cell types including macrophages and fibroblasts. Weight loss, physical activity, and diet are additional modifiable factors beyond smoking cessation that can reduce risk of RA. Future epidemiologic and translational studies leveraging multi-omics approaches will help map the precise sequence of events in RA pathogenesis.

Does smoking affect level of seropositivity in RA? A post-HOC global and inter-country analysis of COMORA cohort

To study the association of smoking status and the level of seropositivity in RA patients from COMORA Cohort. A post hoc analysis of COMORA database included 3439 RA patients was performed. Current smokers or recently quitted (< 3 years) were initially compared to those who never smoked or stopped > 3 years (Group I vs. II) regarding their seropositivity status (high positive, low positive and negative) for Rheumatoid Factor (RF) or Anti-citrullinated antibodies (ACPA). A further comparison was made between current smokers (Group III) and never smoked patients (Group IV). Analysis was also done on the individual country level for the 17 countries included in the COMORA study. Out of 3439 RA patients, 705 (20.5%) were smokers (group I), and 2734 (79.5%) were non-smokers (group II). Significantly more patients in group I, 442 (62.7%), had high levels of seropositivity than those in group II, 1556 (56.9%), [P = 0.006, OR 1.27 (95% CI, 1.07-1.5)]. More current smoker patients (group III-286 out of 456 "62.7%") had high levels of seropositivity than never smoked patients (group IV-1236 out of 2191 "56.4%"), with significant difference [P = 0.013, OR 1.3 (95% CI, 1.06-1.6)]. In 11 countries, higher proportions of patients with high level of seropositivity in group I was found, with statistical significance in four countries. Smoking was associated with higher level of seropositivity in patients with RA in this post hoc analysis, both on a global level and in certain individual countries. As smoking is a modifiable risk factor, studying the effects of quitting smoking on level of seropositivity and other disease parameters is warranted.

Exploring the Evidence for an Immunomodulatory Role of Vitamin D in Juvenile and Adult Rheumatic Disease

Vitamin D is synthesized in the skin following exposure to UVB radiation or is directly absorbed from the diet. Following hydroxylation in the liver and kidneys, vitamin D becomes its bioactive form, 1,25(OH)₂D, which has been described to have potent immunomodulatory capacity. This review will focus on the effect of vitamin D in modulating the dysregulated immune system of autoimmune rheumatic diseases (ARD) patients across age, in particular in arthritis (rheumatoid arthritis and juvenile idiopathic arthritis), and systemic lupus erythematosus (with adult and juvenile onset). As well as delineating the impact of vitamin D on the innate and adaptive immune functions associated with each disease pathology, this review will also summarize and evaluate studies that link vitamin D status with disease prevalence, and supplementation studies that examine the potential benefits of vitamin D on disease outcomes. Exploring this evidence reveals that better designed randomized controlled studies are required to clarify the impact of vitamin D supplementation on ARD outcomes and general health. Considering the accessibility and affordability of vitamin D as a therapeutic option, there is a major unmet need for evidence-based treatment recommendations for the use of vitamin D in this patient population.

Association of Thyroid Function with Posttraumatic Stress Disorder: a Systematic Review and Meta-Analysis

OBJECTIVE

To conduct a systematic review and meta-analysis describing the association of thyroid function with posttraumatic stress disorder (PTSD) in adults.

METHODS

The authors conducted a comprehensive search from databases' inception to July 20, 2018. The meta-analysis included studies that reported mean values and standard deviation (SD) of thyroid hormone levels (thyroid-stimulating hormone &lsqb;TSH], free thyroxine &lsqb;FT4], free triiodothyronine &lsqb;FT3], total T4 &lsqb;TT4], and total T3 &lsqb;TT3]) in patients with PTSD compared with controls. Five reviewers worked independently, in duplicate, to determine study inclusion, extract data, and assess risk of bias. The mean value and SD of the thyroid function tests were used to calculate the mean difference for each variable. Random-effects models for meta-analyses were applied.

RESULTS

The meta-analysis included 10 observational studies at low-to-moderate risk of bias. Studies included 674 adults (373 PTSD, 301 controls). The meta-analytic estimates showed higher levels of FT3 (+0.28 pg/mL; P = .001) and TT3 (+18.90 ng/dL; P = .005) in patients with PTSD compared to controls. There were no differences in TSH, FT4, or TT4 levels between groups. In the subgroup analysis, patients with combat-related PTSD still had higher FT3 (+0.36 pg/mL; P = .0004) and higher TT3 (+31.62 ng/dL; P<.00001) compared with controls. Conversely, patients with non-combat-related PTSD did not have differences in FT3 or TT3 levels compared with controls.

CONCLUSION

There is scarce evidence regarding the association of thyroid disorders with PTSD. These findings add to the growing literature suggesting that thyroid function changes may be associated with PTSD.