What happens before the onset of rheumatoid arthritis?

Nanomedical approaches in the realm of rheumatoid arthritis

Rheumatoid arthritis (RA) is a heterogeneous autoimmune inflammatory disorder defined by the damage to the bone and cartilage in the synovium, which causes joint impairment and an increase in the mortality rate. It is associated with an incompletely elucidated pathophysiological mechanism. Even though disease-modifying antirheumatic drugs have contributed to recent improvements in the standard of care for RA, only a small fraction of patients is able to attain and maintain clinical remission without the necessity for ongoing immunosuppressive drugs. The evolution of tolerance over time as well as patients' inability to respond to currently available therapy can alter the overall management of RA. A significant increase in the research of RA nano therapies due to the possible improvements they may provide over traditional systemic treatments has been observed. New approaches to getting beyond the drawbacks of existing treatments are presented by advancements in the research of nanotherapeutic techniques, particularly drug delivery nano systems. Via passive or active targeting of systemic delivery, therapeutic drugs can be precisely transported to and concentrated in the affected sites. As a result, nanoscale drug delivery systems improve the solubility and bioavailability of certain drugs and reduce dose escalation. In the present paper, we provide a thorough overview of the possible biomedical applications of various nanostructures in the diagnostic and therapeutic management of RA, derived from the shortcomings of conventional therapies. Moreover, the paper suggests the need for improvement on the basis of research directions and properly designed clinical studies.

Effects of alcohol consumption and smoking on risk for RA: results from a Swedish prospective cohort study

Objective

Several, but not all studies, have shown a dose-dependent inverse association with alcohol consumption and rheumatoid arthritis (RA), whereas smoking is an established risk factor for RA. We aimed to study the association between alcohol consumption and RA incidence and investigate a potential interaction between alcohol and smoking habits, regarding RA incidence.

Methods

We used a prospective cohort study, based on 41 068 participants with detailed assessment of alcohol intake, smoking and potential confounders at baseline in 1997. We ascertained a total of 577 incident cases of RA during a mean of 17.7 years of follow-up through linkage to nationwide and essentially complete databases. Multivariate Cox proportional hazards models were used to estimate HR with 95% CI. Interaction on the additive scale between alcohol and smoking was estimated by calculating the attributable proportion due to interaction (AP).

Results

Overall, alcohol consumption was associated with a 30% reduced incidence of RA (HR 0.69, 95% CI 0.55 to 0.86) with a dose–response relationship (p value for trend <0.001) which remained significant after stratification by age and smoking habits. The positive association between smoking and RA incidence was reduced with increasing alcohol consumption (p value for trend <0.001). A synergistic effect was observed between alcohol and smoking (AP 0.40, 95% CI 0.15 to 0.64), indicating that 40% of the cases among the double exposed are due to the interaction per se.

Conclusions

Our findings suggest an inverse association between alcohol consumption and RA incidence, and a synergistic effect between alcohol and smoking.

From Rheumatoid Factor to Anti-Citrullinated Protein Antibodies and Anti-Carbamylated Protein Antibodies for Diagnosis and Prognosis Prediction in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease mainly involving synovial inflammation and articular bone destruction. RA is a heterogeneous disease with diverse clinical presentations, prognoses and therapeutic responses. Following the first discovery of rheumatoid factors (RFs) 80 years ago, the identification of both anti-citrullinated protein antibodies (ACPAs) and anti-carbamylated protein antibodies (anti-CarP Abs) has greatly facilitated approaches toward RA, especially in the fields of early diagnosis and prognosis prediction of the disease. Although these antibodies share many common features and can function synergistically to promote disease progression, they differ mechanistically and have unique clinical relevance. Specifically, these three RA associating auto-antibodies (autoAbs) all precede the development of RA by years. However, while the current evidence suggests a synergic effect of RF and ACPA in predicting the development of RA and an erosive phenotype, controversies exist regarding the additive value of anti-CarP Abs. In the present review, we critically summarize the characteristics of these autoantibodies and focus on their distinct clinical applications in the early identification, clinical manifestations and prognosis prediction of RA. With the advancement of treatment options in the era of biologics, we also discuss the relevance of these autoantibodies in association with RA patient response to therapy.

Periodontal status correlates with anti-citrullinated protein antibodies in first-degree relatives of individuals with rheumatoid arthritis

AIM

To evaluate periodontal status in first-degree relatives of patients with rheumatoid arthritis (FDR-RA) and detect correlation with the presence of anti-citrullinated protein antibodies (ACPAs).

MATERIALS AND METHODS

Rheumatologic status and periodontal status were evaluated in a nested case-control study of FDR-RA with no diagnosis of RA at enrolment. The following parameters were assessed in 34 ACPA-positive (ACPA+) and 65 ACPA-negative (ACPA-) subjects: gingival index (GI), plaque index (PI), probing depth (PD), bleeding on probing (BOP) and clinical attachment level (CAL). We compared the two groups using conditional logistic regression.

RESULTS

In ACPA+ individuals, the mean, PD, BOP, CAL and number of sites per person with PD > 4 mm and BOP were significantly higher compared to the ACPA- group. All ACPA+ subjects had periodontitis: 44.1% presenting moderate and 47.1% severe periodontitis. ACPA- subjects had mainly mild (30.8%) and moderate (27%) periodontitis, differences being significantly different for both moderate periodontitis (p = 0.001) and severe periodontitis (p < 0.001). In multivariable analyses, ACPA status (p = 0.04) and age (p = 0.002) were significantly and independently associated with periodontal conditions.

CONCLUSION

High prevalence and severity of periodontitis in FDR-RA was associated with seropositivity to ACPAs. This further strengthens the hypothesis that periodontitis may be a risk factor in the development of RA.

Modulation of autoimmune arthritis by environmental 'hygiene' and commensal microbiota

Observations in patients with autoimmune diseases and studies in animal models of autoimmunity have revealed that external environmental factors including exposure to microbes and the state of the host gut microbiota can influence susceptibility to autoimmunity and subsequent disease development. Mechanisms underlying these outcomes continue to be elucidated. These include deviation of the cytokine response and imbalance between pathogenic versus regulatory T cell subsets. Furthermore, specific commensal organisms are associated with enhanced severity of arthritis in susceptible individuals, while exposure to certain microbes or helminths can afford protection against this disease. In addition, the role of metabolites (e.g., short-chain fatty acids, tryptophan catabolites), produced either by the microbes themselves or from their action on dietary products, in modulation of arthritis is increasingly being realized. In this context, re-setting of the microbial dysbiosis in RA using prebiotics, probiotics, or fecal microbial transplant is emerging as a promising approach for the prevention and treatment of arthritis. It is hoped that advances in defining the interplay between gut microbiota, dietary products, and bioactive metabolites would help in the development of therapeutic regimen customized for the needs of individual patients in the near future.

Rheumatic Disease Autoantibodies in Patients with Autoimmune Thyroid Diseases

BACKGROUND

Patients with autoimmune thyroid diseases (ATD) such as Graves' disease (GD) and Hashimoto thyroiditis (HT) may have non-organ specific autoantibodies such as antinuclear antibodies (ANA) and rheumatoid factor (RF).

AIM

To study the prevalence of rheumatic autoantibodies in a group of ATD patients without known rheumatic diseases and to evaluate its association with the patients' epidemiological and treatment profiles. To follow positive non-organ specific autoantibody-positive ATD individuals to investigate whether they will develop a rheumatic disorder.

METHODS

A sample of 154 ATD patients (70 HT and 84 GD; mean age 45.3 ± 14.2) had determination of ANA by immunofluorescence, using hep-2 cells as substrate, extractable nuclear antigen profile by ELISA kits and RF by latex agglutination. Epidemiological and treatment profiles were obtained through chart review. These patients were followed for the mean period of 5 years, between 2010 and 2015.

RESULTS

Positive ANA was found in 17.5% (27/154) of the patients: anti-Ro/SS-A in 4/154 (2.5%); anti-RNP in 4/154 (2.5%), and anti-La/SS-B in 3/154 (1.9%). None had anti-Sm antibodies. RF was detected in 12/154 (7.7%) of ATD patients and was more common in older individuals (p = 0.007). There was a positive association between the presence of RF and ANA (p = 0.03; OR 3.89; 95% CI 1.1-13.3). None of the patients with positive autoantibodies developed clinical rheumatic diseases during the period of observation.

CONCLUSION

We found rheumatic autoantibodies in 17.5% of ATD patients without rheumatic diseases. None of them were associated with the appearance of clinical rheumatic disorder during the period of 5 years.

Interleukin-36 receptor mediates the crosstalk between plasma cells and synovial fibroblasts

The IL-1 family member IL-36α has proinflammatory and pathogenic properties in psoriasis. IL-36α binds to the IL-36 receptor leading to nuclear factor kappa B/mitogen activated protein kinase mediated cytokine release. The IL-36R antagonist prevents recruitment of IL-1 receptor accessory protein and therefore IL-36-dependent cell activation. In inflamed human tissue, we previously could show that resident B cells and plasma cells (PC) express IL-36α. Further, fibroblast-like synoviocytes (FLS) produced proinflammatory cytokines upon IL-36α-stimulation. We hypothesize an IL-36-specific crosstalk between B cells/PCs and FLS permitting a proinflammatory B cell niche. Here, we firstly demonstrated that B cell lines and B cells from healthy donors express IL-36α and stimulation increased IL-36α in B cells and primary plasmablasts/PCs. Moreover, FLS respond specifically to IL-36α by proliferation and production of matrix metalloproteinases via p38/HSP27 signaling. Importantly, IL-36R-deficiency abrogated IL-36α-induced production of inflammatory mediators in FLS and changed the intrinsic FLS-phenotype. Using an in vitro co-culture system, we could show that IL-36R-deficient FLS had a limited capacity to support PC survival compared to wild-type FLS. Hence, we demonstrated an IL-36R-dependent crosstalk between B cells/PCs and FLS. Our data support the concept of initiation and maintenance of a proinflammatory niche by B cells in the joints.

Absence of surrogate light chain results in spontaneous autoreactive germinal centres expanding V(H)81X-expressing B cells

Random recombination of antibody heavy- and light-chain genes results in a diverse B-cell receptor (BCR) repertoire including self-reactive BCRs. However, tolerance mechanisms that prevent the development of self-reactive B cells remain incompletely understood. The absence of the surrogate light chain, which assembles with antibody heavy chain forming a pre-BCR, leads to production of antinuclear antibodies (ANAs). Here we show that the naive follicular B-cell pool is enriched for cells expressing prototypic ANA heavy chains in these mice in a non-autoimmune background with a broad antibody repertoire. This results in the spontaneous formation of T-cell-dependent germinal centres that are enriched with B cells expressing prototypic ANA heavy chains. However, peripheral tolerance appears maintained by selection thresholds on cells entering the memory B-cell and plasma cell pools, as exemplified by the exclusion of cells expressing the intrinsically self-reactive V(H)81X from both pools.

Clinical and serological analysis of patients with positive anticyclic citrullinated Peptide antibodies referred through a Rheumatology Central Triage System

OBJECTIVE

Anticitrullinated protein antibodies (ACPA) are a highly specific and sensitive biomarker for the diagnosis of rheumatoid arthritis (RA). Some patients who were found to have a positive ACPA test were referred to our Rheumatology Central Triage (CT; Calgary, Alberta, Canada) for assessment by a rheumatologist. The objectives of our study were to determine the clinical accuracy of ACPA in establishing a diagnosis of RA in a real-time clinical setting.

METHODS

Cases that met 3 criteria were included in the study: (1) referred to the CT over 3 calendar years (n = 20,389), (2) reason for referral was a positive ACPA test (n = 568), and (3) evaluated by a certified rheumatologist (n = 314). An administrative serological database was used to retrieve specific ACPA results.

RESULTS

Of patients referred through our CT for evaluation of a positive ACPA test, 57.6% received a diagnosis of RA; the remainder had a variety of other diagnoses, some of which might be considered early RA (9%). The predictive values of ACPA for the diagnosis of RA were increased when rheumatoid factor (RF) results were included in the analysis. When definite and possible RA were combined and the prevalence of moderate/high ACPA was compared to all other individuals, the positive and negative predictive values for moderate/high ACPA for RA were 74.3% and 68.4%, respectively.

CONCLUSION

About 58% of patients with a positive ACPA referred through a triage system for a rheumatologist opinion received a diagnosis of RA at their first visit. RF provides additional useful information to guide the diagnosis and urgency of referral.

Rheumatoid factors: clinical applications

Rheumatoid factors are antibodies directed against the Fc region of immunoglobulin G. First detected in patients with rheumatoid arthritis 70 years ago, they can also be found in patients with other autoimmune and nonautoimmune conditions, as well as in healthy subjects. Rheumatoid factors form part of the workup for the differential diagnosis of arthropathies. In clinical practice, it is recommended to measure anti-cyclic citrullinated peptide antibodies and rheumatoid factors together because anti-cyclic citrullinated peptide antibodies alone are only moderately sensitive, and the combination of the two markers improves diagnostic accuracy, especially in the case of early rheumatoid arthritis. Furthermore, different rheumatoid factor isotypes alone or in combination can be helpful when managing rheumatoid arthritis patients, from the time of diagnosis until deciding on the choice of therapeutic strategy.

New insights into the genetics of immune responses in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease with a strong genetic component. Numerous aberrant immune responses have been described during the evolution of the disease. In later years, the appearance of anti-citrullinated protein antibodies (ACPAs) has become a hallmark for the diagnosis and prognosis of RA. The post-translational transformation of arginine residues of proteins and peptides into citrulline (citrullination) is a natural process in the body, but for unknown reasons autoreactivity towards citrullinated residues may develop in disposed individuals. ACPAs are often found years before clinical manifestations. ACPAs are present in about 70% of RA patients and constitute an important disease marker, distinguishing patient groups with different prognoses and different responses to various treatments. Inside the human leukocyte antigen (HLA) region, some HLA-DRB1 alleles are strongly associated with their production. Genome-wide association studies in large patient cohorts have defined a great number of single nucleotide polymorphisms (SNPs) outside of the HLA region that are associated with ACPA positive (ACPA+) RA. The SNPs are generally located close to or within genes involved in the immune response or signal transduction in immune cells. Some environmental factors such as tobacco smoking are also positively correlated with ACPA production. In this review, we will describe the genes and loci associated with ACPA+ RA or ACPA- RA and attempt to clarify their potential role in the development of the disease.

A case-control study on the association between rheumatoid arthritis and bladder pain syndrome/interstitial cystitis

AIM

While bladder pain syndrome/interstitial cystitis (BPS/IC) has been suggested by a number of studies to have autoimmune character, no population-based study to date has been conducted investigating its association with rheumatoid arthritis (RA). This study aimed to examine the association between IC/BPS and having previously been diagnosed with RA.

METHODS

We conducted this study by using administrative claims data sourced from the Taiwan National Health Insurance Database. Our study included 9,269 cases with BPS/IC and 46,345 randomly selected controls. Conditional logistic regression was performed to calculate the odds ratio (OR) for the association between previously diagnosed RA and IC/BPS.

RESULTS

RA was found among 202 (2.2%) cases and 504 (1.12%) controls. Conditional logistic regression analysis suggested that when compared with controls, the OR for prior RA among cases was 1.66 (95% CI = 1.47-1.87, P < 0.001) after adjusting for diabetes, hypertension, coronary heart disease, obesity, hyperlipidemia, chronic pelvic pain, irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, depression, panic disorder, migraine, sicca syndrome, allergy, endometriosis, asthma, overactive bladder, tobacco use disorder, and alcohol abuse. Additionally, BPS/IC was consistently and significantly associated with a previous diagnosis of RA regardless of prescription drug use; the OR for prior RA among groups prescribed ≤1 type of disease-modifying antirheumatic drug (DMARD), two types of DMARDs, and ≥3 types of DMARDs or TNF-alpha inhibitor when compared to controls were 1.49 (95% CI = 1.28-1.72), 1.91 (95% CI = 1.38-2.68), and 2.36 (95% CI = 1.77-3.17), respectively.

CONCLUSIONS

There is an association between RA and BPS/IC after adjusting for socio-demographic characteristics and medical co-morbidities.

Strategies to prevent rheumatoid arthritis in high-risk patients

PURPOSE OF REVIEW

To examine potential interventions, including modification of environmental risk factors and use of pharmacologic agents, in at-risk populations to prevent progression to (or development of) rheumatoid arthritis (RA). This review is timely given the increasing interest in early intervention strategies and new opportunities to identify patients early in the pathogenesis of RA.

RECENT FINDINGS

Despite the growing literature demonstrating a link between anticitrullinated protein antibodies, synovitis, genetic and environmental risk factors such as smoking and RA, there are no studies that have evaluated the effect of modifying environmental risk factors in late preclinical RA. This article describes several studies that have evaluated the ability of pharmacologic interventions to modify outcomes in patients at risk for RA.

SUMMARY

The prevention of RA in at-risk populations is feasible; however, this will necessitate novel efforts to identify patients very early in disease development to examine the effectiveness and cost of preventive interventions.

Unresolved issues in biologic therapy for rheumatoid arthritis

The advent of biologic therapies for the treatment of rheumatoid arthritis (RA) has radically changed this therapeutic area. The currently available biologic agents have been studied extensively as part of their development and also during their subsequent years of use in clinical practice; as a result, the knowledge base regarding these therapeutics is very large. Nonetheless, a number of important questions remain and some key issues are still incompletely understood. In this Review, I discuss a number of these unresolved issues, including: the correct placement of biologic therapies in the long-term evolution of the RA disease process, and the expectations associated with such use; comparisons of therapeutic strategies that include conventional as well as biologic agents; optimal dosing of biologic agents; the elusive goal of personalized therapy; and an appraisal of the real impact of biologic therapy on patients' lives. It is concluded that, despite these unresolved issues, important progress has been made and many additional advances in our understanding can be expected during the coming years.

Association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope and smoking status in Brazilian patients with rheumatoid arthritis

INTRODUCTION

Epstein-Barr virus exposure appears to be an environmental trigger for rheumatoid arthritis that interacts with other risk factors. Relationships among anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status have been observed in patients with rheumatoid arthritis from different populations.

OBJECTIVE

To perform an association analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status in Brazilian patients with rheumatoid arthritis.

METHODS

In a case-control study, 140 rheumatoid arthritis patients and 143 healthy volunteers who were matched for age, sex, and ethnicity were recruited. Anti-Epstein-Barr nuclear antigen-1 antibodies and anti-cyclic citrullinated peptide antibodies were examined using an enzyme-linked immunosorbent assay, and shared epitope alleles were identified by genotyping. Smoking information was collected from all subjects. A comparative analysis of anti-Epstein-Barr nuclear antigen-1 antibodies, anti-cyclic citrullinated peptide antibodies, the shared epitope, and smoking status was performed in the patient group. Logistic regression analysis models were used to analyze the risk of rheumatoid arthritis.

RESULTS

Anti-Epstein-Barr nuclear antigen-1 antibodies were not associated with anti-cyclic citrullinated peptide antibodies, shared epitope alleles, or smoking status. Anti-cyclic citrullinated peptide antibody positivity was significantly higher in smoking patients with shared epitope alleles (OR = 3.82). In a multivariate logistic regression analysis using stepwise selection, only anti-cyclic citrullinated peptide antibodies were found to be independently associated with rheumatoid arthritis (OR = 247.9).

CONCLUSION

Anti-Epstein-Barr nuclear antigen-1 antibodies did not increase the risk of rheumatoid arthritis and were not associated with the rheumatoid arthritis risk factors studied. Smoking and shared epitope alleles were correlated with anti-cyclic citrullinated peptide-antibody-positive rheumatoid arthritis. Of the risk factors, only anticyclic citrullinated peptides antibodies were independently associated with rheumatoid arthritis susceptibility.

Patient-reported events preceding the onset of rheumatoid arthritis: possible clues to aetiology

AIMS

Patients with rheumatoid arthritis (RA) often report events that they believe may have caused their disease. We attempted to characterize such causal events and the possible relationship between these and outcomes.

METHODS

Between 1996 and 2004, 1,787 adult patients were included in the Better Anti-Rheumatic FarmacOTherapy (BARFOT) early RA study in Sweden. Six possible causal events at baseline were predefined. Disease Activity Score 28-joint count (DAS28) and treatment were registered at inclusion and at three, six and 12 months. The European League against Rheumatism (EULAR) response criteria were used.

RESULTS

A total of 1,652 patients (92%) answered the question about possible causal events. Thirty per cent (490) of the patients believed that some event in particular had caused their RA. Sixteen per cent of the patients thought that infection, 4.4% psychological trauma, 4.1% physical trauma, 2.8% surgery, 1.5% pregnancy and 1.2% vaccination had been the cause. Younger patients attributed previous infection to their RA more often than older patients. There were no differences in EULAR response up to one year between patients who reported some event or infection and patients who did not. RA thought to be caused by infection showed a seasonal trend in the month of onset. Women reported that trauma had been a cause of their RA more often than men.

CONCLUSION

Thirty per cent of the patients reported some causal event and 16% reported infection to be the cause of their RA. There were differences in gender and age in what patients reported as the cause of their RA.

The association between the PTPN22 1858C>T variant and type 1 diabetes depends on HLA risk and GAD65 autoantibodies

The single nucleotide polymorphism 1858C>T in the PTPN22 gene is associated with type 1 diabetes (T1D) in several populations. Earlier reports have suggested that the association may be modified by human leukocyte antigen (HLA), as well as by islet autoantibodies. In a large case-control study of Swedish incident T1D patients and controls, 0-34 years of age, we tested whether the odds ratio (OR) measure of association was dependent on HLA or autoantibodies against the islet autoantigens glutamic acid decarboxylase 65 kDa autoantibodies (GADA), insulin, islet antigen-2, or islet cell. The association between the carrier status of 1858C>T allele in PTPN22 (PTPN22(CT+TT)) and T1D was modified by HLA. In addition, in GADA-positive T1D, the OR was 2.83 (2.00, 3.99), whereas in GADA-negative T1D, the OR was 1.41 (0.98, 2.04) (P for comparison=0.007). The OR of association between PTPN22(CT+TT) and GADA-positive T1D declined with increasing HLA-risk category from 6.12 to 1.54 (P=0.003); no such change was detected in GADA-negative T1D (P=0.722) (P for comparison=0.001). However, the absolute difference in risk between PTPN22(CC) and PTPN22(CT+TT) subjects with high-risk HLA was five times higher than that for subjects with low-risk HLA. We hypothesize that the altered T-cell function because of the PTPN22(1858C>T) polymorphism is exclusively associated with GADA-positive T1D at diagnosis.

The potential application of nicotinic acetylcholine receptor agonists for the treatment of rheumatoid arthritis

Although the disease-modifying anti-rheumatic drugs (DMARD) have been widely used in clinics, rheumatoid arthritis (RA) is not completely curable so far. Hence, to seek new drugs for the treatment of RA has become a pursuing goal of rheumatologists and orthopedic surgeons. Since the major pathological characteristic of RA is inflammation, the exploration of anti-inflammatory drugs has become a hotspot. Moreover, the anti-inflammatory and anti-nociceptive functions of nicotinic acetylcholine receptors as well as the related mechanisms have been recently discovered. Based on the above-mentioned, it is promising that the nicotinic acetylcholine receptor agonists will be applied for the treatment of RA. Following in vitro, in vivo experiments as well as clinical trials will even strengthen this viewpoint and more RA patients will benefit from the application of such agents.