Familial risks and heritability of rheumatoid arthritis: role of rheumatoid factor/anti-citrullinated protein antibody status, number and type of affected relatives, sex, and age

Family History of Rheumatic, Autoimmune, and Nonautoimmune Diseases and Risk of Rheumatoid Arthritis

OBJECTIVE

Since comorbidities such as autoimmune diseases may be associated with rheumatoid arthritis (RA) risk, we hypothesized that a family history of these other conditions might also predict RA. Therefore, we aimed to determine the association between family history of 79 comorbidities and RA.

METHODS

This case-control study identified 821 cases of RA in the Mayo Clinic Biobank (positive predictive value 95%) and matched 3 controls to each case based on age, sex, recruitment year, and location. Patients self reported family history and characteristics (adjusted). Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for RA risk according to the presence of family history for each comorbidity, adjusted for body mass index, race, and smoking.

RESULTS

Family history of several conditions was associated with developing RA, including rheumatic autoimmune diseases (ORadj 1.89 [95% CI 1.41-2.52]), pulmonary fibrosis (ORadj 2.12 [95% CI 1.16-3.80]), inflammatory bowel disease (ORadj 1.45 [95% CI 1.05-1.98]), hyper/hypothyroidism (ORadj 1.34 [95% CI 1.10-1.63]), and obstructive sleep apnea (ORadj 1.28 [95% CI 1.05-1.55]). Parkinson's disease and type 2 diabetes mellitus were associated with a statistically decreased risk of RA that did not reach the prespecified significance threshold of P < 0.01 (ORadj 0.70 [95% CI 0.49-0.98] and ORadj 0.81 [95% CI 0.67-0.97], respectively). Analyses among 143 cases of incident RA were similar and also suggested an association with a family history of autism (OR 10.5 [95% CI 2.51-71.3]).

CONCLUSION

Family history of several autoimmune and nonautoimmune comorbidities was associated with increased risk of RA, providing an opportunity to identify novel populations at risk for RA.

Importance of family planning in patients with immune-mediated inflammatory diseases: a multidisciplinary approach

BACKGROUND AND OBJECTIVES

Family planning in women with immune-mediated inflammatory diseases is a challenge for healthcare teams, highlighting the need for standardized available evidence to provide patients with objective and agreed information. This study reflects the work performed by a multidisciplinary team in reviewing available scientific evidence, and the strategy agreed for family planning, pregnancy, postpartum, and breastfeeding in patients with immune-mediated inflammatory diseases.

METHODS

A literature search was conducted, information was structured across the different stages (preconception, pregnancy, postpartum and breastfeeding), and an on-site meeting was convened, in which patients and healthcare providers participated.

RESULTS

Specific materials, which are included in this work, were developed to guide clinical decisions to be agreed upon by patients and healthcare providers.

CONCLUSION

These materials meet the need for validated and updated information on the approach and use of indicated drugs for professionals responsible for the management of immune-mediated inflammatory diseases.

Biomarkers to Personalize the Treatment of Rheumatoid Arthritis: Focus on Autoantibodies and Pharmacogenetics

Rheumatoid arthritis (RA) is a chronic inflammatory disease that is very complex and heterogeneous. If not adequately treated, RA patients are likely to manifest excess of morbidity and disability with an important impact on the quality of life. Pharmacological treatment is based on the administration of the disease-modifying antirheumatic drugs (DMARDs), subdivided into conventional synthetic (csDMARDs), targeted synthetic (tsDMARDs), and biological (bDMARDs). bDMARDs are now frequently administered in patients, both as alternative treatment and together with csDMARDs. Unfortunately, there is a therapeutic response variability both to old and new drugs. Therefore, to identify pre-therapeutic and on-treatment predictors of response is a priority. This review aims to summarize recent advances in understanding the causes of the variability in treatment response in RA, with particular attention to predictive potential of autoantibodies and DMARD pharmacogenetics. In recent years, several biomarkers have been proposed to personalize the therapy. Unfortunately, a magic bullet does not exist, as many factors concur to disease susceptibility and treatment outcomes, acting around the patient’s congenital background. Models integrating demographic, clinical, biochemical, and genetic data are needed to enhance the predictive capacity of specific factors singularly considered to optimize RA treatment in light of multidisciplinary patient management.

Anti-carbamylated protein and peptide antibodies as potential inflammatory joint biomarkers in the relatives of rheumatoid arthritis patients

OBJECTIVE

Antibodies against carbamylated proteins/peptide (CarP) have been associated with severity in rheumatoid arthritis (RA) patients. However, their role in risk groups, specific targets and relation with periodontal disease (PD) is uncertain yet. The aim of this study was evaluated the association between the levels of anti-CarP with clinical manifestation, human leukocyte antigen (HLA) alleles, periodontal activity markers, PD diagnosis, PD severity, and presence of Porphyromonas gingivalis (P gingivalis) in relatives of patients with RA.

METHODS

One hundred and twenty-four individuals with a family history of RA in first-degree relatives (FDR) and 124 healthy individuals gender- and age-matched, RA activity was assessed. Antibodies against carbamylated protein anti-FCS-Carp and 2 carbamylated peptides of fibrinogen were selected (anti-Ca-Fib2, anti-Ca-Fib3).

RESULTS

Anti-FCS-Carp-positive, anti-Ca-Fib2 and anti-Ca-Fib3 were more frequent in FDR than controls (25.0% vs 14.5%, 34.7% vs 15.3% and 33.1% vs 11.3%, respectively). Anti-FCS-CarP were associated with the HLA-DRB1-SE* 1402 allele (P = .035) and highly sensitive C-reactive protein levels (P = .016), the anti-Ca-Fib2 antibodies were associated with the HLA-DRB1-SE* 1501 allele (P = .03), with non-SE* 0901 allele (P = .01), the anti-Ca-Fib3 was associated with positive rheumatoid factor (P = .0012). The FDR condition was associated with the presence of anti-Ca-Fib3 (odds ratio [OR] =4.7; 95% CI = 1.8-11.7; P = .001) and painful joints (OR = 2.2; 95% CI = 1.01-4.68; P = .045); we also detected an important trend toward the presence of P gingivalis (OR = 1.9; 95% CI = 0.9-3.7; P = .062).

CONCLUSION

The presence of anti-FCS-Carp, anti-Ca-Fib3 and anti-Ca-Fib2 antibodies may have a role for these antibodies as early biomarkers in the development of RA, probably including additional mechanisms related with other non-SE alleles; the anti-peptide antibodies proposed in the present study may represent a simpler way to identify antibodies directed to a specific target.

Familial aggregation and heritability of ankylosing spondylitis - a Swedish nested case-control study

OBJECTIVES

AS is known to be a highly heritable disease, but previous studies on the magnitude of the familial aggregation and heritability of AS have been small and inconclusive, with familial relative risks ranging from 17 to 94. We aimed to improve estimates of these factors by studying families of all subjects diagnosed with AS in Sweden over a period of 16 years and to investigate if familial risks vary by sex or type of relative.

METHODS

In a nested case-control study, we identified AS index patients from the National Patient Register (NPR) and the Swedish Rheumatology Quality Register (SRQ) between 2001 and 2016. Each index patient was matched on age and sex to up to 50 general population controls. First-degree relatives of index patients and controls were identified through the Multi-Generation Register, with disease status ascertained in the NPR and SRQ. Familial risks were defined as odds ratios (ORs) of having AS when exposed to a first-degree relative with AS, using conditional logistic regression.

RESULTS

The overall familial OR for AS was 19.4 (95% CI 18.1, 20.8). Estimates were similar for different relative types and by sex, but having more than one affected relative resulted in a higher risk [OR 68.0 (95% CI 51.3, 90.1)]. Heritability, estimated by assuming sibling risks were completely due to genetics, was 77% (95% CI 73, 80).

CONCLUSION

Although the familial risk and heritability of AS are higher than for most other diseases, we report estimates that are substantially lower than commonly referenced numbers for AS from other populations.

Genomic imprinting analyses identify maternal effects as a cause of phenotypic variability in type 1 diabetes and rheumatoid arthritis

Imprinted genes, giving rise to parent-of-origin effects (POEs), have been hypothesised to affect type 1 diabetes (T1D) and rheumatoid arthritis (RA). However, maternal effects may also play a role. By using a mixed model that is able to simultaneously consider all kinds of POEs, the importance of POEs for the development of T1D and RA was investigated in a variance components analysis. The analysis was based on Swedish population-scale pedigree data. With P = 0.18 (T1D) and P = 0.26 (RA) imprinting variances were not significant. Explaining up to 19.00% (± 2.00%) and 15.00% (± 6.00%) of the phenotypic variance, the maternal environmental variance was significant for T1D (P = 1.60 × 10-24) and for RA (P = 0.02). For the first time, the existence of maternal genetic effects on RA was indicated, contributing up to 16.00% (± 3.00%) of the total variance. Environmental factors such as the social economic index, the number of offspring, birth year as well as their interactions with sex showed large effects.

Infectious Triggers in Periodontitis and the Gut in Rheumatoid Arthritis (RA): A Complex Story About Association and Causality

Rheumatoid arthritis (RA) is a systemic immune mediated inflammatory disease of unknown origin, which is predominantly affecting the joints. Antibodies against citrullinated peptides are a rather specific immunological hallmark of this heterogeneous entity. Furthermore, certain sequences of the third hypervariable region of human leukocyte antigen (HLA)-DR class II major histocompatibility (MHC) molecules, the so called "shared epitope" sequences, appear to promote autoantibody positive types of RA. However, MHC-II molecule and other genetic associations with RA could not be linked to immune responses against specific citrullinated peptides, nor do genetic factors fully explain the origin of RA. Consequently, non-genetic factors must play an important role in the complex interaction of endogenous and exogenous disease factors. Tobacco smoking was the first environmental factor that was associated with onset and severity of RA. Notably, smoking is also an established risk factor for oral diseases. Furthermore, smoking is associated with extra-articular RA manifestations such as interstitial lung disease in anatomical proximity to the airway mucosa, but also with subcutaneous rheumatoid nodules. In the mouth, Porphyromonas gingivalis is a periodontal pathogen with unique citrullinating capacity of foreign microbial antigens as well as candidate RA autoantigens. Although the original hypothesis that this single pathogen is causative for RA remained unproven, epidemiological as well as experimental evidence linking periodontitis (PD) with RA is rapidly accumulating. Other periopathogens such as Aggregatibacter actinomycetemcomitans and Prevotella intermedia were also proposed to play a specific immunodominant role in context of RA. However, demonstration of T cell reactivity against citrullinated, MHC-II presented autoantigens from RA synovium coinciding with immunity against Prevotella copri (Pc.), a gut microbe attracted attention to another mucosal site, the intestine. Pc. was accumulated in the feces of clinically healthy subjects with citrulline directed immune responses and was correlated with RA onset. In conclusion, we retrieved more than one line of evidence for mucosal sites and different microbial taxa to be potentially involved in the development of RA. This review gives an overview of infectious agents and mucosal pathologies, and discusses the current evidence for causality between different exogenous or mucosal factors and systemic inflammation in RA.

High frequency of rheumatic regional pain syndromes in first-degree relatives of patients with rheumatoid arthritis

First-degree relatives (FDR) of patients with rheumatoid arthritis (RA) have a higher risk for the development of RA. In the stages prior to the development of arthritis, nonspecific musculoskeletal (MSK) manifestations may occur. The aim of the study is to describe the frequency of rheumatic regional pain syndromes (RRPS) in FDR of RA patients. A cross-sectional study was carried out from July 2016 to September 2018. Parents, offspring, and siblings of RA patients completed the Community Oriented Program in the Rheumatic Diseases (COPCORD) questionnaire. Rheumatoid factor (RF) IgG, IgM, and IgA; anticitrullinated peptide antibodies (ACPAs); C-reactive protein (CRP); and erythrocyte sedimentation rate (ESR) were determined. All subjects with a positive COPCORD (defined by the presence of musculoskeletal pain) were evaluated and classified. Three hundred thirty-five FDRs participated, 75.8% were female, mean age of 44.15 years; 138 (41.2%) were diagnosed with at least one RRPS; 72 (21.5%) had rotator cuff tendinitis, 51 (15.2%) pes anserine bursitis, and 39 (11.6) lateral epicondylitis; RA was diagnosed in 24 (7.16%) subjects, undifferentiated arthritis (UA) in 30 (8.9%) and inflammatory arthralgia (AI) in 104 (31%). We found anti-CCP positivity in 6.8%, RF IgA in 22.3%, RF IgM in 48.6%, and RF IgG in 8.9%. The presence of RRPS was higher in this RA-FDR group compared to general population. Clinical evaluation of this risk group should include screening for RRPS.

Current Understanding of an Emerging Role of HLA-DRB1 Gene in Rheumatoid Arthritis-From Research to Clinical Practice

Rheumatoid arthritis (RA) is an autoimmune disease with an unclear pathogenic mechanism. However, it has been proven that the key underlying risk factor is a genetic predisposition. Association studies of the HLA-DRB1 gene clearly indicate its importance in RA morbidity. This review presents the current state of knowledge on the impact of HLA-DRB1 gene, functioning both as a component of the patient’s genome and as an environmental risk factor. The impact of known HLA-DRB1 risk variants on the specific structure of the polymorphic HLA-DR molecule, and epitope binding affinity, is presented. The issues of the potential influence of HLA-DRB1 on the occurrence of non-articular disease manifestations and response to treatment are also discussed. A deeper understanding of the role of the HLA-DRB1 gene is essential to explore the complex nature of RA, which is a result of multiple contributing factors, including genetic, epigenetic and environmental factors. It also creates new opportunities to develop modern and personalized forms of therapy.

The importance of differences; On environment and its interactions with genes and immunity in the causation of rheumatoid arthritis

The current review uses rheumatoid arthritis (RA) as a prominent example for how studies on the interplay between environmental and genetic factors in defined subsets of a disease can be used to formulate aetiological hypotheses that subsequently can be tested for causality using molecular and functional studies. Major discussed findings are that exposures to airways from many different noxious agents including cigarette smoke, silica dust and more interact with major susceptibility genes, mainly HLA-DR genetic variants in triggering antigen-specific immune reactions specific for RA. We also discuss how several other environmental and lifestyle factors, including microbial, neural and metabolic factors, can influence risk for RA in ways that are different in different subsets of RA.The description of these processes in RA provides the best example so far in any immune-mediated disease of how triggering of immunity at one anatomical site in the context of known environmental and genetic factors subsequently can lead to symptoms that precede the classical inflammatory disease symptoms and later contribute also to the classical RA joint inflammation. The findings referred to in the review have led to a change of paradigms for very early therapy and prevention of RA and to efforts towards what we have named 'personalized prevention'. We believe that the progress described here for RA will be of relevance for research and practice also in other immune-mediated diseases.

Preferences for treatments to prevent rheumatoid arthritis in Canada and the influence of shared decision-making

OBJECTIVE

To elicit and compare preferences of patients and first-degree relatives and rheumatologists for preventive treatments for rheumatoid arthritis, understand the influence of shared decision-making, and predict the probability of uptake of the preventive treatments currently being studied.

METHODS

An online discrete choice experiment was completed by patients and their first-degree relatives and rheumatologists. Results were analysed using mixed logit model to estimate preferences for the key features of treatments. Preferences for features of treatments were used to predict the probability of uptake of seven preventive treatment options.

RESULTS

A total of 108 potential recipients (78 patients and 30 of their first-degree relatives) and 39 rheumatologists completed the survey. Preferences of patients/first-degree relatives and rheumatologists were similar (shared decision-making was most important, followed by the risk of side effects and potential benefit), but subtle differences existed; rheumatologists placed greater importance on certainty in evidence than patients/first-degree relatives, who felt that how a treatment was taken was more important. Predicted uptake suggested that 38% (95% CI 19%, 58%) of patients/first-degree relatives would not take a preventive treatment, compared with 12% (95% CI - 4%, 27%) of rheumatologists. A consistent finding across all groups was a preference for non-biologic disease-modifying anti-rheumatic drugs.

CONCLUSION

Only relatively safe options for preventive treatment are likely to be acceptable to at-risk populations. This study of preventive treatments highlights that the preferences of physicians and recipients of treatment should take a central role in the design of clinical studies as well as in decisions to initiate treatments. Key Points • This paper is the first to compare preferences for preventive treatments between rheumatologists and patients and at-risk individuals. • The results of this study indicate that patients and at-risk individuals, as well as rheumatologists, are likely to prefer the safest options as preventive treatment, even if the potential benefit of these is lower. • Although preferences of patients and at-risk individuals are similar to those of rheumatologists, the choice of preventive treatment may differ between groups; this is important as shared decision-making was a critical factor in treatment decision-making. • Preferences of physicians and recipients of treatment should take a central role in the design of clinical studies as well as in decisions to initiate treatments.

Skin inflammation associated with arthritis, synovitis and enthesitis. Part 2: rheumatoid arthritis, reactive arthritis, Reiter's syndrome, Lyme borreliosis, dermatomyositis and lupus erythematosus

Syndromes associated with concurrent skin and joint inflammation frequently pose a therapeutic challenge for both dermatologists and rheumatologists. In part 1 of this review, we discussed psoriatic arthritis as well as the autoinflammatory disorders SAPHO syndrome, Still's disease and Behçet's disease. Part 2 will address rheumatoid arthritis, reactive arthritis, Reiter's syndrome and Lyme borreliosis. In addition, we will discuss dermatomyositis and lupus erythematosus, two common autoimmune disorders that frequently present with both cutaneous and joint involvement. For each of the aforementioned disorders, we will highlight aspects of epidemiology, pathogenesis, clinical presentation, diagnosis and treatment.

Association of Genetic vs Environmental Factors in Swedish Adoptees With Clinically Significant Tinnitus

Question

Is clinically significant tinnitus associated with genetic factors?

Findings

In this study of national registry data from 11 060 adoptees, 19 015 adoptive parents, and 17 025 biological parents, a heritability of 32% and no association of shared environment with the transmission of tinnitus were found.

Meaning

The present study suggests that genetic factors are associated with the familial clustering of severe tinnitus.

Importance

No effective treatments are currently available for severe tinnitus, which affects 1% of the population and lowers the quality of life. The factors that contribute to the transition from mild to severe tinnitus are poorly known. Before performing genetic analyses and determining the mechanisms involved in the development of severe tinnitus, its heritability needs to be determined.

Objectives

To examine whether clinically significant tinnitus is associated with genetic factors and to evaluate the genetic risk in the transmission of tinnitus using adoptees.

Design, Setting, and Participants

Data from adoptees and their biological and adoptive parents from Swedish nationwide registers were collected from January 1, 1964, to December 31, 2015, and used to separate genetic from environmental factors in familial clustering. In all, 11 060 adoptees, 19 015 adoptive parents, and 17 025 biological parents were investigated. The study used a cohort design and a case-control approach to study genetic and nongenetic factors in tinnitus among adoptees.

Main Outcomes and Measures

The primary outcome was odds ratio (OR) of tinnitus in adoptees with at least 1 affected biological parent compared with adoptees without any affected biological parent using logistic regression. The secondary outcome was OR in adoptees with at least 1 affected adoptive parent compared with adoptees without any affected adoptive parent.

Results

A total of 1029 patients (440 [42.8%] male; mean [SD] age, 62 [14] years) with tinnitus were identified. The prevalence of diagnosed tinnitus was 2.2%. The OR for tinnitus was 2.22 for adoptees (95% CI, 1.03-4.81) of biological parents diagnosed with tinnitus, whereas the OR was 1.00 (95% CI, 0.43-2.32) for adoptees from adoptive parents diagnosed with tinnitus. Mean (SE) heritability determined using tetrachoric correlations was 31% (14%).

Conclusions and Relevance

The findings suggest that genetic factors are associated with the familial clustering of clinically significant tinnitus with no shared-environment association, revealing that the transition from negligible to severe tinnitus may be associated with genetic factors. These findings may provide insight for future genetic analyses that focus on severe tinnitus.

Rheumatoid Arthritis Patients, Both Newly Diagnosed and Methotrexate Treated, Show More DNA Methylation Differences in CD4+ Memory Than in CD4+ Naïve T Cells

Background: Differences in DNA methylation have been reported in B and T lymphocyte populations, including CD4⁺ T cells, isolated from rheumatoid arthritis (RA) patients when compared to healthy controls. CD4⁺ T cells are a heterogeneous cell type with subpopulations displaying distinct DNA methylation patterns. In this study, we investigated DNA methylation using reduced representation bisulfite sequencing in two CD4⁺ T cell populations (CD4⁺ memory and naïve cells) in three groups: newly diagnosed, disease modifying antirheumatic drugs (DMARD) naïve RA patients (N = 11), methotrexate (MTX) treated RA patients (N = 18), and healthy controls (N = 9) matched for age, gender and smoking status.

Results: Analyses of these data revealed significantly more differentially methylated positions (DMPs) in CD4⁺ memory than in CD4⁺ naïve T cells (904 vs. 19 DMPs) in RA patients compared to controls. The majority of DMPs (72%) identified in newly diagnosed and DMARD naïve RA patients with active disease showed increased DNA methylation (39 DMPs), whereas most DMPs (80%) identified in the MTX treated RA patients in remission displayed decreased DNA methylation (694 DMPs). Interestingly, we also found that about one third of the 101 known RA risk loci overlapped (±500 kb) with the DMPs. Notably, introns of the UBASH3A gene harbor both the lead RA risk SNP and two DMPs in CD4⁺ memory T cells.

Conclusion: Our results suggest that RA associated DNA methylation differences vary between the two T cell subsets, but are also influenced by RA characteristics such as disease activity, disease duration and/or MTX treatment.

Is the prevention of rheumatoid arthritis possible?

Preclinical phases of rheumatoid arthritis (RA) have been described, genetic and environmental risk factors for RA development have been identified, and several biomarkers of RA have been detected long before the clinical onset of the disease; all of which have opened the possibility for preventive interventions. Several studies are currently exploring pharmacological and non-pharmacological interventions to prevent the development of RA. We will review the evidence for prevention of RA and discuss key challenges for preventive interventions, including identification of the adequate target population, the risks of applying potentially harmful and expensive therapies to asymptomatic at-risk individuals, and the importance of taking into account the preferences of individuals at risk regarding preventive treatment options.

Comparison of methods to construct a genetic risk score for prediction of rheumatoid arthritis in the population-based Nord-Trøndelag Health Study, Norway

Objectives

To evaluate selection methods among published single-nucleotide polymorphisms (SNPs) associated with RA to construct predictive genetic risk scores (GRSs) in a population-based setting.

Methods

The Nord-Trøndelag Health (HUNT) Study is a prospective cohort study among the whole adult population of northern Trøndelag, Norway. Participants in HUNT2 (1995–1997) and HUNT3 (2006–2008) were included (489 RA cases, 61 584 controls). The initial SNP selection from relevant genome-wide studies included 269 SNPs from 30 studies. Following different selection criteria, SNPs were weighted by published odds ratios. The sum of each person’s carriage of all weighted susceptibility variants was calculated for each GRS.

Results

The best-fitting risk score included 27 SNPs [weighted genetic risk score 27 (wGRS27)] and was identified using P-value selection criterion ≤5 × 10−8, the largest possible SNP selection without high linkage disequilibrium (r2 &lt; 0.8), and lasso regression to select for positive coefficients. In a logistic regression model adjusted for gender, age and ever smoking, wGRS27 was associated with RA [odds ratio 1.86 (95% CI 1.71, 2.04) for each s.d. increase, P &lt; 0.001]. The AUC was 0.76 (95% CI 0.74, 0.78). The positive and negative predictive values were 1.6% and 99.7%, respectively, and the positive predictive value was not improved in sensitivity analyses subselecting participants to illustrate settings with increased RA prevalences. Other schemes selected more SNPs but resulted in GRSs with lower predictive ability.

Conclusion

Constructing a wGRS based on a smaller selection of informative SNPs improved predictive ability. Even with a relatively high AUC, the low PPV illustrates that there was a large overlap in risk variants among RA patients and controls, precluding clinical usefulness.

Association of adipokines with rheumatic disease activity indexes and periodontal disease in patients with early rheumatoid arthritis and their first-degree relatives

OBJECTIVE

To evaluate the adipokine levels in early rheumatoid arthritis (eRA) and first-degree relatives (FDR) of patients with RA and establish their association with rheumatic disease activity and periodontal variables.

METHOD

A cross-sectional study with eRA patients, FDR and a healthy population. Adipokine levels, clinical, joint radiological indexes and periodontal variables were evaluated. A descriptive, bivariate analysis was performed based on the adipokine levels by χ² , Fisher's test and Mann-Whitney U test. A logistic regression was made for associations.

RESULTS

High leptin levels were associated with the diagnosis of eRA (odds ratio [OR] = 2.79; 95% CI 1.54-5.07). Early rheumatoid arthritis with high adiponectin levels was less likely to have Multidimensional Health Assessment Questionnaire score >3, body mass index (BMI) >25 and Routine Assessment of Patient Index Data 3 score >12 (OR = 0.16; 95% CI 0.03-0.72). Early rheumatoid arthritis was more likely to present high leptin and interleukin (IL)6 levels with low adiponectin simultaneously (OR = 5.03; 95% CI 1.05-24.0). High leptin levels were associated with the FDR adjusted for IgG2 Porphyromonas gingivalis, swollen joints, P gingivalis and low IL6 (OR = 2.57; 95% CI 1.14-5.95).

CONCLUSION

High adipokine levels in eRA may modulate the disease activity. Having more than 1 adipokine at high serum levels is associated with increased disability, disease activity and BMI, indicating that RA is controlled by adiponectin levels in the early stages of the disease. High leptin levels, presence of P gingivalis and swollen joints may be the factors associated with the development of RA in FDR.

The family history of rheumatoid arthritis in anti-cyclic citrullinated peptide antibody-positive patient is not a predictor of poor clinical presentation and treatment response with modern classification criteria and treatment strategy: the ANSWER cohort study

A family history of rheumatoid arthritis (RA) is a strong risk factor for developing RA, affecting both genetically and environmentally. However, whether family history provides clinically relevant information in the modern classification and treatment remains largely unknown. This study aimed to determine whether a family history of RA is associated with a different clinical presentation of RA and treatment response. We retrospectively evaluated the demographic data and disease activity of newly diagnosed RA patients at baseline, 1 year, and 2 years after onset, using the ANSWER (Kansai consortium for the well-being of rheumatic disease patients) cohort data. Thirty-one patients (11.9%) among 260 newly diagnosed RA patients had a family history of RA up to second degree. There was no significant difference in the age at onset, time from onset to first visit, sex, positivity or value of rheumatoid factor or anti-cyclic citrullinated peptide antibody (ACPA), or disease activity between patients with and without a family history of RA. However, patients who had a family history of RA and were ACPA positive showed significantly lower erythrocyte sedimentation rate, and C-reactive protein. Disease activity in patients with a family history was not worse at baseline, after 1 year or 2 years of treatment. The Larsen score 2 years after onset was equivalent between the patients with and without a family history of RA in ACPA-positive patients. Family history of RA in ACPA-positive patients is not associated with high disease activity at baseline and is not a predictor of poor outcome 2 years after onset.

A Prospective Study of the Development of Inflammatory Arthritis in the Family Members of Indigenous North American People With Rheumatoid Arthritis

OBJECTIVE

To determine the incidence of inflammatory arthritis and autoantibody prevalence in Indigenous North American people.

METHODS

Unaffected relatives of Indigenous North Americans with rheumatoid arthritis (RA) from central Canada and Alaska were systematically monitored from 2005 to 2017. Rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) were tested at every visit, and a subset was tested for ACPA fine specificity using a custom multiplex assay. Multistate models based on all available study visits were developed to determine the likelihood of transitioning between autoantibody states, or to inflammatory arthritis.

RESULTS

Eighteen of 374 relatives (4.8%) developed inflammatory arthritis during follow-up (after a mean ± SD of 4.7 ± 2.4 years), yielding a transition rate of 9.2 cases/1,000 person-years. Thirty percent of those who developed inflammatory arthritis were seronegative at baseline, but all were seropositive at inflammatory arthritis onset. Although 30% of ACPA/RF double-seropositive individuals developed inflammatory arthritis (after 3.2 ± 2.2 years), the majority of these individuals did not develop inflammatory arthritis. Multistate modeling indicated a 71% and 68% likelihood of ACPA and RF seropositive states, respectively, reverting to a seronegative state after 5 years, and a 39% likelihood of an ACPA/RF double-seropositive state becoming seronegative. Fine specificity testing demonstrated an expansion of the ACPA repertoire prior to the development of inflammatory arthritis.

CONCLUSION

Despite a high incidence of inflammatory arthritis in this cohort of at-risk relatives of Indigenous North Americans with RA, a large proportion of autoantibody-positive individuals do not develop inflammatory arthritis and revert back to an autoantibody-negative state.

Heritability of glomerulonephritis: A Swedish adoption study

BACKGROUND

Glomerulonephritis clusters in families. However, infections are common inducers of glomerulonephritis and may also cluster in families. Studies of adoptees and their biological and adoptive parents may disentangle genetic from environmental causes of familial clustering. This is the first adoption study aimed to estimate the genetic contribution to the familial transmission of glomerulonephritis.

MATERIALS AND METHODS

We performed a family study for Swedish-born adoptees (born 1945-2000) and their biological and adoptive parents. The Swedish Multi-Generation Register was linked to the Hospital Inpatient Register for the period 1964-2012 and the Hospital Outpatient Register for 2001-2012. Odds ratio (OR) for glomerulonephritis was determined for adoptees with a biological parent with glomerulonephritis compared with adoptees without an affected biological parent. Similarly, the OR for glomerulonephritis was also determined in adoptees with an affected adoptive parent compared with adoptees without an affected adoptive parent. Heritability was estimated to be twice the observed tetrachoric correlation among adoptees and biological parents, under the assumption that only additive genetic factors contribute to the similarity between biological parents and adoptees.

RESULTS

The OR for glomerulonephritis was 4.08 in adoptees (95% confidence interval [CI] 1.79-9.27, P-value = 0.001) of biological parents diagnosed with glomerulonephritis. The OR for glomerulonephritis was 1.67 in adoptees (95% CI 0.53-5.26, P-value = 0.380) of adoptive parents diagnosed with glomerulonephritis. The heritability was 48%.

CONCLUSION

Family history of glomerulonephritis in a biological parent is a risk factor for glomerulonephritis. The present study indicates that genetic factors play an important role in the aetiology of glomerulonephritis.

Burden for Parents of Patients With Schizophrenia-A Nationwide Comparative Study of Parents of Offspring With Rheumatoid Arthritis, Multiple Sclerosis, Epilepsy, and Healthy Controls

BACKGROUND

The study aimed to (1) compare the risk of health care use, adverse health status, and work productivity loss of parents of patients with schizophrenia to parents of patients with multiple sclerosis (MS), rheumatoid arthritis (RA), epilepsy, and healthy controls; and (2) evaluate such outcome measures while considering disease severity of schizophrenia.

METHODS

Based on linkage of Swedish registers, at least one parent was included (n = 18215) of patients with schizophrenia (information 2006-2013, n = 10883). Similarly, parental information was linked to patients with MS, RA, epilepsy, and matched healthy controls, comprising 11292, 15516, 34715, and 18408 parents, respectively. Disease severity of schizophrenia was analyzed. Different regression models yielding odds ratios (OR), hazard ratios (HR), or relative risks (RR) with 95% confidence intervals (CI) were run.

RESULTS

Psychiatric health care use, mainly due to anxiety and affective disorders, showed a strongly increasing trend for parents of patients with schizophrenia throughout the observation period. During the follow-up, these parents had an up to 2.7 times higher risk of specialized psychiatric health care and receipt of social welfare benefits than other parents. Parents of the moderately severely ill patients with schizophrenia had higher risk estimates for psychiatric health care (RR: 1.12; 95% CI: 1.07-1.17) compared with parents of least severely ill patients.

CONCLUSIONS

Parents of patients with schizophrenia have a considerably higher risk of psychiatric health care and social welfare benefit receipt than other parents. Psychiatric health care use worsens over time and with increasing disease severity of the offspring.

Preventing rheumatoid arthritis: Preferences for and predicted uptake of preventive treatments among high risk individuals

OBJECTIVE

To understand preferences for and estimate the likely uptake of preventive treatments currently being evaluated in randomized controlled trials with individuals at increased risk of developing rheumatoid arthritis (RA).

METHODS

Focus groups were used to identify key attributes of potential preventive treatment for RA (reduction in risk of RA, how treatment is taken, chance of side effects, certainty in estimates, health care providers opinion). A web-based discrete choice experiment (DCE) was administered to people at-risk of developing RA, asking them to first choose their preferred of two hypothetical preventive RA treatments, and then between their preferred treatment and 'no treatment for now.' DCE data was analyzed using conditional logit regression to estimate the significance and relative importance of attributes in influencing preferences.

RESULTS

Two-hundred and eighty-eight first-degree relatives (60% female; 66% aged 18-39 years) completed all tasks in the survey. Fourteen out of fifteen attribute levels significantly influenced preferences for treatments. How treatment is taken (oral vs. infusion β0.983, p<0.001), increasing reduction in risk of RA (β0.922, p<0.001), health care professional preference (β0.900, p<0.001), and avoiding irreversible (β0.839, p<0.001) or reversible serious side effects (β0.799, p<0.001) were most influential. Predicted uptake was high for non-biologic drugs (e.g. 84% hydroxycholoroquine), but very low for atorvastatin (8%) and biologics (<6%).

CONCLUSION

Decisions to take preventative treatments are complex, and uptake depends on how treatments can compromise on convenience, potential risks and benefits, and recommendations/preferences of health care professionals. This evidence contributes to understanding whether different preventative treatment strategies are likely to be acceptable to target populations.

Prevotella copri in individuals at risk for rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) has been associated with a relative expansion of faecal Prevotellaceae. To determine the microbiome composition and prevalence of Prevotella spp. in a group of individuals at increased risk for RA, but prior to the development of the disease.

METHODS

In an ongoing cohort study of first-degree relatives (FDRs) of patients with RA, we identified 'FDR controls', asymptomatic and without autoantibodies, and individuals in pre-clinical RA stages, who had either developed anticitrullinated peptide antibodies or rheumatoid factor positivity and/or symptoms and signs associated with possible RA. Stool sampling and culture-independent microbiota analyses were performed followed by descriptive statistics and statistical analyses of community structures.

RESULTS

A total of 133 participants were included, of which 50 were categorised as 'FDR controls' and 83 in 'pre-clinical RA stages'. The microbiota of individuals in 'pre-clinical RA stages' was significantly altered compared with FDR controls. We found a significant enrichment of the bacterial family Prevotellaceae, particularly Prevotella spp., in the 'pre-clinical RA' group (p=0.04).

CONCLUSIONS

Prevotella spp. enrichment in individuals in pre-clinical stages of RA, before the onset of RA, suggests a role of intestinal dysbiosis in the development of RA.

Comparative effectiveness of abatacept, rituximab, tocilizumab and TNFi biologics in RA: results from the nationwide Swedish register

OBJECTIVES

Current guidelines rank abatacept, rituximab, tocilizumab and TNF-inhibitors (TNFi) as having equal effectiveness for the treatment of RA, at least as second line therapies. These recommendations are mainly based on meta-analysis of randomized controlled trials, with few direct drug-drug comparisons. Our objective was to compare the real-world absolute and relative effectiveness among RA patients starting any of the available biologic DMARDs (bDMARDs).

METHODS

We used the Swedish Rheumatology Register to identify patients with RA initiating TNFi, rituximab, abatacept or tocilizumab in 2010-2016 as first bDMARD (n = 9333), or after switch from TNFi as first bDMARD (n = 3941). National Swedish registers provided additional covariates and censoring events. Effectiveness was assessed 3 and 12 months after treatment start, as the proportion remaining on therapy and with EULAR Good Response, HAQ improvement >0.2, zero swollen/tender joints and CDAI remission. Adjusted differences were estimated with multivariable linear regression.

RESULTS

Patients starting non-TNFi (vs TNFi) as first bDMARD had a higher proportion remaining on drug and reaching most response outcomes as first bDMARD (1-year EULAR Good Response/HAQ improvement: TNFi 24.9/25.4%, rituximab 28.6/37.2%, abatacept 31.9/33.7%, tocilizumab 50.9/43.1%). After switch from a first TNFi, rituximab and tocilizumab, but not abatacept, were associated with significantly better response measures than TNFi (1-year EULAR Good Response/HAQ improvement: TNFi 11.6/16.1%, rituximab 24.8/33.2%, abatacept 13.1/17.5%, tocilizumab 34.1/29.4%). Differences remained significant after adjusting for potential confounders.

CONCLUSION

Treatment outcomes among RA patients treated in Swedish clinical practice are in line with a superior effectiveness of non-TNFi bDMARDs, in particular tocilizumab and rituximab, compared with TNFi.

Perceptions of first-degree relatives of patients with rheumatoid arthritis about lifestyle modifications and pharmacological interventions to reduce the risk of rheumatoid arthritis development: a qualitative interview study

BACKGROUND

There is increasing interest in the identification of people at risk of rheumatoid arthritis (RA) to monitor the emergence of early symptoms (and thus allow early therapy), offer lifestyle advice to reduce the impact of environmental risk factors and potentially offer preventive pharmacological treatment for those at high risk. Close biological relatives of people with RA are at an increased risk of developing RA and are therefore potential candidates for research studies, screening initiatives and preventive interventions. To ensure the success of approaches of this kind, a greater understanding of the perceptions of this group relating to preventive measures is needed.

METHODS

Twenty-four first-degree relatives of patients with an existing diagnosis of RA from the UK, three from Germany and seven from Austria (age: 21-67 years) took part in semi-structured interviews exploring their perceptions of RA risk, preventive medicine and lifestyle changes to reduce RA risk. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis.

RESULTS

Many first-degree relatives indicated that they anticipated being happy to make lifestyle changes such as losing weight or changing their diet to modify their risk of developing RA. Participants further indicated that in order to make any lifestyle changes it would be useful to know their personal risk of developing RA. Others implied they would not contemplate making lifestyle changes, including stopping smoking, unless this would significantly reduce or eliminate their risk of developing RA. Many first-degree relatives had more negative perceptions about taking preventive medication to reduce their risk of RA, and listed concerns about potential side effects as one of the reasons for not wanting to take preventive medicines. Others would be more willing to consider drug interventions although some indicated that they would wish to wait until symptoms developed.

CONCLUSIONS

Information targeted at those considered to be at risk of RA should contain information about RA, the extent to which risk can be quantified at an individual level and how risk levels may differ depending on whether early symptoms are present. The benefits (and risks) of lifestyle changes and pharmacological interventions as potential preventive measures should be clearly described.

The potential of PTPN22 as a therapeutic target for rheumatoid arthritis

INTRODUCTION

PTPN22 encodes a lymphoid-specific tyrosine phosphatase (LYP) that is a master regulator of the immune response. This gene is a major susceptibility factor for a wide range of autoimmune conditions, including rheumatoid arthritis (RA) for which it represents the strongest non-HLA contributor to disease risk. A missense PTPN22 allele (R620W) affecting the protein-protein interaction of LYP with other relevant players was described as the functional variant of the association. This review will focus on the role of PTPN22 in the pathogenic mechanisms underlying RA predisposition and discuss the possibility of developing LYP-based treatment strategies with a potential application in clinical practice. Areas covered: This review covers the literature showing how PTPN22 is implicated in signalling pathways involved in the autoimmune and autoinflammatory processes underlying RA. Insights obtained from studies aimed at developing novel selective LYP suppressors for treating RA are summarized. Expert opinion: Targeting key risk factors during the early steps of the disease may represent a good strategy to accomplish complete disease remission. As cumulating evidences suggest that PTPN22 R620W is a gain-of-function variant, a growing interest in developing LYP inhibitors has arisen. The potential efficacy and possible application of such compounds are discussed.

Survivin Measurement improves Clinical Prediction of Transition From Arthralgia to RA-Biomarkers to Improve Clinical Sensitivity of Transition From Arthralgia to RA

Background: Arthralgia often predates development of rheumatoid arthritis (RA). A set of joint symptoms commonly found in patients during their transition from arthralgia to RA, has been recently proposed.

Aim: To combine clinical and serological markers and to improve recognition of imminent rheumatoid arthritis (RA) among patients with arthralgia.

Methods: The total of 1,743 first-visit patients attending the rheumatology ward in Gothenburg for joint symptoms were identified during 12 consecutive months. Among those, 63 patients were classified as RA, 73 had undifferentiated arthritis and 180 had unexplained arthralgia. New RA cases, which prospectively developed during 48 months, comprised the preclinical (pre) RA group. The joint symptoms of the first-visit were analyzed aiming to distinguish patients with arthralgia and arthritis, and patients with pre-RA, who later developed the disease. The receiver operating characteristics curves were constructed. In the model, symptoms with the odds ratio >2.0 between the arthralgia and pre-RA were combined with information about RA-specific antibodies, C-reactive protein (CRP), and survivin in serum.

Results: The proposed set of clinical symptoms distinguished the arthralgia patients from RA and pre-RA. Presence of survivin in serum showed strong association with clinical joint symptoms in arthralgia. A combination of symptoms in several small joint areas, increasing number of joints with symptoms, and patient's experience of swelling in small hand joints at the first visit identified pre-RA cases with 93% specificity. Grouping those symptoms with information about survivin, RA-specific antibodies, and CRP (or gender) in the final algorithm achieved 91% specificity and 55.2% of positive prediction for transition from arthralgia to RA.

Conclusion: Clinical and serological parameters in combination aid recognition of imminent RA among arthralgia patients with appropriate sensitivity.

Disclosure of Personalized Rheumatoid Arthritis Risk Using Genetics, Biomarkers, and Lifestyle Factors to Motivate Health Behavior Improvements: A Randomized Controlled Trial

OBJECTIVE

To determine the effect of disclosure of rheumatoid arthritis (RA) risk personalized with genetics, biomarkers, and lifestyle factors on health behavior intentions.

METHODS

We performed a randomized controlled trial among first-degree relatives without RA. Subjects assigned to the Personalized Risk Estimator for Rheumatoid Arthritis (PRE-RA) group received the web-based PRE-RA tool for RA risk factor education and disclosure of personalized RA risk estimates, including genotype/autoantibody results and behaviors (n = 158). Subjects assigned to the comparison arm received standard RA education (n = 80). The primary outcome was readiness for change based on the trans-theoretical model, using validated contemplation ladder scales. Increased motivation to improve RA risk-related behaviors (smoking, diet, exercise, or dental hygiene) was defined as an increase in any ladder score compared to baseline, assessed immediately, 6 weeks, and 6 months post-intervention. Subjects reported behavior change at each visit. We performed intent-to-treat analyses using generalized estimating equations for the binary outcome.

RESULTS

Subjects randomized to PRE-RA were more likely to increase ladder scores over post-intervention assessments (relative risk 1.23, 95% confidence interval [95% CI] 1.01, 1.51) than those randomized to nonpersonalized education. At 6 months, 63.9% of PRE-RA subjects and 50.0% of comparison subjects increased motivation to improve behaviors (age-adjusted difference 15.8%; 95% CI 2.8%, 28.8%). Compared to nonpersonalized education, more PRE-RA subjects increased fish intake (45.0% versus 22.1%; P = 0.005), brushed more frequently (40.7% versus 22.9%; P = 0.01), flossed more frequently (55.7% versus 34.8%; P = 0.004), and quit smoking (62.5% versus 0.0% among 11 smokers; P = 0.18).

CONCLUSION

Disclosure of RA risk personalized with genotype/biomarker results and behaviors increased motivation to improve RA risk-related behaviors. Personalized medicine approaches may motivate health behavior improvements for those at risk for RA and provide rationale for larger studies evaluating effects of behavior changes on clinical outcomes, such as RA-related autoantibody production or RA development.

Heritability of Mitral Regurgitation: Observations From the Framingham Heart Study and Swedish Population

BACKGROUND

Familial aggregation has been described for primary mitral regurgitation (MR) caused by mitral valve prolapse. We hypothesized that heritability of MR exists across different MR subtypes including nonprimary MR.

METHODS AND RESULTS

Study participants were FHS (Framingham Heart Study) Generation 3 (Gen 3) and Gen 2 cohort participants and all adult Swedish siblings born after 1932 identified in 1997 and followed through 2010. MR was defined as ≥ mild regurgitation on color Doppler in FHS and from International Classification of Diseases codes in Sweden. We estimated the association of sibling MR with MR in Gen 2/Gen 3/Swedish siblings. We also estimated heritability of MR in 539 FHS pedigrees (7580 individuals). Among 5132 FHS Gen 2/Gen 3 participants with sibling information, 1062 had MR. Of siblings with sibling MR, 28% (500/1797) had MR compared with 17% (562/3335) without sibling MR (multivariable-adjusted odds ratio, 1.20; 95% confidence interval [CI], 1.01-1.43; P=0.04). When we combined parental and sibling data in FHS pedigrees, heritability of MR was estimated at 0.15 (95% CI, 0.07-0.23), 0.12 (95% CI, 0.04-0.20) excluding mitral valve prolapse, and 0.44 (95% CI, 0.15-0.73) for ≥ moderate MR only (all P<0.05). In Sweden, sibling MR was associated with a hazard ratio of 3.57 (95% CI, 2.21-5.76; P<0.001) for development of MR.

CONCLUSIONS

Familial clustering of MR exists in the community, supporting a genetic susceptibility common to primary and nonprimary MR. Further studies are needed to elucidate the common regulatory pathways that may lead to MR irrespective of its cause.

Rheumatoid arthritis: pathological mechanisms and modern pharmacologic therapies

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that primarily affects the lining of the synovial joints and is associated with progressive disability, premature death, and socioeconomic burdens. A better understanding of how the pathological mechanisms drive the deterioration of RA progress in individuals is urgently required in order to develop therapies that will effectively treat patients at each stage of the disease progress. Here we dissect the etiology and pathology at specific stages: (i) triggering, (ii) maturation, (iii) targeting, and (iv) fulminant stage, concomitant with hyperplastic synovium, cartilage damage, bone erosion, and systemic consequences. Modern pharmacologic therapies (including conventional, biological, and novel potential small molecule disease-modifying anti-rheumatic drugs) remain the mainstay of RA treatment and there has been significant progress toward achieving disease remission without joint deformity. Despite this, a significant proportion of RA patients do not effectively respond to the current therapies and thus new drugs are urgently required. This review discusses recent advances of our  understanding of RA pathogenesis, disease modifying drugs, and provides perspectives on next generation therapeutics for RA.

The preclinical stages of rheumatoid arthritis (RA) represent a golden window for the development of therapies which could someday prevent the onset of clinical disease. The autoimmune processes underpinning RA usually begin many years before symptoms such as joint pain and stiffness emerge. Recent studies have identified some of the key cellular players driving these processes and begun to unpick how genetic and environmental risk factors combine to trigger them; they also suggest the existence of several distinct subtypes of RA, which require further exploration. Jiake Xu at the University of Western Australia in Perth and colleagues review current treatment strategies for RA and how such insights could ultimately lead to the earlier diagnosis of RA - as well as providing new opportunities for drug treatment and prevention through behavioral changes in high-risk individuals.

Patient characteristics influence the choice of biological drug in RA, and will make non-TNFi biologics appear more harmful than TNFi biologics

Objectives

With the wide range of biological disease-modifying anti-rheumatic drugs (bDMARDs) available for treating rheumatoid arthritis (RA), and limited evidence to guide the choice for individual patients, we wished to evaluate whether patient characteristics influence the choice of bDMARD in clinical practice, and to quantify the extent to which this would bias direct comparisons of treatment outcome.

Methods

Register-based study of all Swedish patients with RA initiating necrosis factor inhibitor (TNFi), rituximab, abatacept or tocilizumab in 2011–2015 as their first bDMARD (n=6481), or after switch from TNFi as first bDMARD (n=2829). Group differences in demographics, clinical characteristics and medical history were assessed in multivariable regression models. Predicted differences in safety and treatment outcomes were calculated as a function of patient characteristics, through regression modelling based on observed outcomes among patients with RA starting bDMARDs 2006–2010.

Results

Patients starting non-TNFi were older than those starting TNFi, had lower socioeconomic status, higher disease activity and higher burden of diseases including malignancy, serious infections and diabetes. Differences were most pronounced at first bDMARD initiation. These factors were linked to treatment outcome independent of therapy, yielding worse apparent safety and effectiveness for non-TNFi biologics, most extreme for rituximab. Standardising to the age/sex distribution of the TNFi group reduced differences considerably.

Conclusions

There was significant channelling of older and less healthy patients with RA to non-TNFi bDMARDs, in particular as first bDMARD. Whether this channelling represents a maximised benefit/risk ratio is unclear. Unless differences in age, medical history and disease activity are accounted for, they will substantially confound non-randomised comparative studies of available bDMARDs’ safety and effectiveness.

Review: Genetics and the Classification of Arthritis in Adults and Children

Current classification of primary inflammatory arthritis begins from the assumption that adults and children are different. No form of juvenile idiopathic arthritis bears the same name as an adult arthritis, a nomenclature gap with implications for both clinical care and research. Recent genetic data have raised questions regarding this adult/pediatric divide, revealing instead broad patterns that span the age spectrum. Combining these genetic patterns with demographic and clinical data, we propose that inflammatory arthritis can be segregated into 4 main clusters, largely irrespective of pediatric or adult onset: seropositive, seronegative (likely including a distinct group that usually begins in early childhood), spondyloarthritis, and systemic. Each of these broad clusters is internally heterogeneous, highlighting the need for further study to resolve etiologically discrete entities. Eliminating divisions based on arbitrary age cutoffs will enhance opportunities for collaboration between adult and pediatric rheumatologists, thereby helping to promote the understanding and treatment of arthritis.

Preventing progression from arthralgia to arthritis: targeting the right patients

Early treatment is associated with improved outcomes in patients with rheumatoid arthritis (RA), suggesting that a 'window of opportunity', in which the disease is most susceptible to disease-modifying treatment, exists. Autoantibodies and markers of systemic inflammation can be present long before clinical arthritis, and maturation of the immune response seems to coincide with the development of RA. The pre-arthritis phase associated with symptoms such as as joint pain without clinical arthritis (athralgia) is now hypothesized to fall within the aforementioned window of opportunity. Consequently, disease modulation in this phase might prevent the occurrence of clinically apparent arthritis, which would result in a persistent disease course if untreated. Several ongoing proof-of-concept trials are now testing this hypothesis. This Review highlights the importance of adequate risk prediction for the correct design, execution and interpretation of results of these prevention trials, as well as considerations when translating these findings into clinical practice. The patients' perspectives are discussed, and the accuracy with which RA development can be predicted in patients presenting with arthralgia is evaluated. Currently, the best starting position for preventive studies is proposed to be the inclusion of patients with an increased risk of RA, such as those identified as fulfilling the EULAR definition of 'arthralgia suspicious for progression to RA'.

Heritability of End-Stage Renal Disease: A Swedish Adoption Study

BACKGROUND/AIMS

The heritability of end-stage renal disease (ESRD) among adoptees has not been examined so far. By studying adoptees and their biological and adoptive parents, it is possible to differentiate between the genetic causes and environmental causes of familial aggregation. This nationwide study aimed to disentangle the genetic and shared environmental contribution to the familial transmission of ESRD.

METHODS

We performed a family study for Swedish-born adoptees (born between 1945 until 1995) and their biological and adoptive parents. The Swedish Multi-Generation Register was linked to the National Patient Registry for the period 1964-2012. ESRD was defined as patients in active uremic care, that is, chronic dialysis or kidney transplantation. OR for ESRD was determined for adoptees with an affected biological parent with ESRD compared with adoptees without a biological parent with ESRD. The OR for ESRD was also calculated in adoptees with an adoptive parent with ESRD compared with adoptees with an adoptive parent without ESRD. Moreover, heritability for ESRD was estimated with Falconer's regression.

RESULTS

A total of 111 adoptees, 463 adoptive parents, and 397 biological parents were affected by ESRD. The OR for ESRD was 6.41 in adoptees (95% CI 2.96-13.89) of biological parents diagnosed with ESRD. The OR for ESRD was 2.40 in adoptees (95% CI 0.76-7.60) of adoptive parents diagnosed with ESRD. The heritability of ESRD was 59.5 ± 18.2%.

CONCLUSION

The family history of ESRD in a biological parent is an important risk factor for ESRD. The high heritability indicates that genetic factors play an important role in understanding the etiology of ESRD.

Malignant Neoplasms in Patients With Rheumatoid Arthritis Treated With Tumor Necrosis Factor Inhibitors, Tocilizumab, Abatacept, or Rituximab in Clinical Practice: A Nationwide Cohort Study From Sweden

IMPORTANCE

Considering the widespread and increasing use of biological immunomodulators (biological disease-modifying antirheumatic drugs [bDMARDs]) to treat chronic inflammatory conditions, and the concern that immunomodulation may alter cancer risk and progression, the limited available data on use of these therapies as used in clinical practice and cancer risks are a concern.

OBJECTIVE

To assess the risk of incident malignant neoplasms in patients with rheumatoid arthritis (RA) treated with bDMARDs.

DESIGN, SETTING, AND PARTICIPANTS

This was a national register-based prospective cohort study of the public health care system in Sweden from 2006 to 2015. Cohorts of patients with RA initiating treatment with tocilizumab (n = 1798), abatacept (n = 2021), and rituximab (n = 3586), a tumor necrosis factor inhibitor (TNFi) as first-ever (n = 10 782) or second-ever (n = 4347) bDMARD, a biologics-naive cohort treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) (n = 46 610), and a general population comparator cohort (n = 107 491).

EXPOSURES

Treatment with tocilizumab, abatacept, rituximab, or TNFi.

MAIN OUTCOMES AND MEASURES

Outcomes included a first invasive solid or hematologic malignant neoplasm, or skin cancer. Hazard ratios were calculated using Cox-regression, adjusted for age, sex, disease and treatment characteristics, and educational level.

RESULTS

We identified a total of 15 129 initiations of TNFi as the first or second bDMARD, 7405 initiations of other bDMARDs, and 46 610 csDMARD users. The mean age varied from 58 to 64 years, and the proportion of female patients varied from 71% to 80%, across the 7 cohorts under study. The observed numbers of events (crude incidence per 100 000 person-years) for a first invasive solid or hematologic malignant neoplasm were 50 (959) for tocilizumab, 61 (1026) for abatacept, 141 (1074) for rituximab, 478 (978) for initiators of TNFi as first bDMARD, and 169 (917) for TNFi as second bDMARD. There were no statistically significant differences between initiators of a first or second TNFi, or other bDMARDs, and bDMARD-naive RA for any of a total of 25 drug- and outcome-specific comparisons, with 1 exception (abatacept and increased risk of squamous cell skin cancer).

CONCLUSIONS AND RELEVANCE

The overall risk of cancer among patients with RA initiating TNFi as first or second bDMARD, tocilizumab, abatacept, or rituximab does not differ substantially from that of biologic drug-naive, csDMARD-treated patients with RA, although altered risks for specific cancer types, or those with longer latency, cannot be excluded.

A Swedish national adoption study of risk of irritable bowel syndrome (IBS)

Objectives

Irritable bowel syndrome (IBS) clusters in families, but the familial risk of IBS has not been determined in adoptees. Studying adoptees and their biological and adoptive parents is a strong study design for separating genetic from environmental causes of familial clustering. This nationwide study aimed to separate the biological (genetic) and familial environmental contribution to the familial transmission of IBS.

Methods

We performed a family study for Swedish-born adoptees born from 1951 until 1995, and their biological and adoptive parents. The Swedish Multigeneration Register was linked to the Hospital Register (inpatients and outpatients) for the period 1964-2012 and the Swedish Outpatient Care Register for 2001-2012, and the Swedish Primary Healthcare register for 1989-2012. ORs for IBS were calculated for adoptees with an affected biological parent with IBS compared with adoptees without a biological parent with IBS. The OR for IBS was also determined in adoptees with an adoptive parent with IBS compared with adoptees without an adoptive parent with IBS. Heritability h² (±SE) was also determined.

Results

The ORs for IBS were 1.67 in adoptees (95% CI 1.06 to 2.62) of biological parents diagnosed with IBS. The ORs for IBS were 0.88 in adoptees (95% CI 0.48 to 1.63) of adoptive parents diagnosed with IBS. The heritability was 19.5%±8.5%.

Conclusions

The present study indicates that biological (genetic) factors are important for the familial clustering of IBS. The heritability calculated is in the range from twin studies and suggests that heritability may be estimated in adoptees.

Familial aggregation of rheumatoid arthritis and co-aggregation of autoimmune diseases in affected families: a nationwide population-based study

Objective

The aim was to estimate familial relative risk (RR) for RA and other autoimmune diseases and the genetic contribution to RA phenotypic variance (heritability).

Methods

This study used the Taiwan National Health Insurance Research Database to identify all National Health Insurance registered beneficiaries (n = 23 658 577) in 2010; among them, 37 482 individuals had RA. We estimated familial RRs and 95% CIs of RA and other autoimmune diseases using marginal Cox proportional models and heritability of RA using a threshold liability model.

Results

The RR (95% CI) for RA was 328.27 (135.95, 795.63) for twins of RA patients; 11.97 (8.68, 16.52) for siblings; 4.86 (4.16, 5.67) for parents; 4.65 (3.92, 5.50) for offspring; and 2.32 (1.83, 2.95) for spouses. Using a threshold liability model, we estimated that familial transmission was 59.4% (95% CI: 50.3, 69.5%) and that heritability was 43.5% (33.9, 54.1%). The RR (95% CI) in individuals with a first-degree relative with RA was 2.91 (2.49, 3.42) for SLE; 2.92 (1.62, 5.25) for SSc; 3.13 (2.50, 3.93) for primary SS; 0.95 (0.36, 2.51) for idiopathic inflammatory myositis; 1.96 (1.54, 2.48) for type 1 diabetes mellitus; 3.32 (1.82, 5.95) for multiple sclerosis; 1.31 (1.31, 2.43) for IBD; 2.76 (2.46, 3.10) for AS; and 1.65 (1.54, 1.77) for psoriasis.

Conclusion

The risks of RA and other autoimmune diseases increased in individuals with an RA family history. Approximately two-thirds of RA phenotypic variation is explained by familial factors.

Genotypic variability based association identifies novel non-additive loci DHCR7 and IRF4 in sero-negative rheumatoid arthritis

Sero-negative rheumatoid arthritis (RA) is a highly heterogeneous disorder with only a few additive loci identified to date. We report a genotypic variability-based genome-wide association study (vGWAS) of six cohorts of sero-negative RA recruited in Europe and the US that were genotyped with the Immunochip. A two-stage approach was used: (1) a mixed model to partition dichotomous phenotypes into an additive component and non-additive residuals on the liability scale and (2) the Levene’s test to assess equality of the residual variances across genotype groups. The vGWAS identified rs2852853 (P = 1.3e-08, DHCR7) and rs62389423 (P = 1.8e-05, near IRF4) in addition to two previously identified loci (HLA-DQB1 and ANKRD55), which were all statistically validated using cross validation. DHCR7 encodes an enzyme important in cutaneous synthesis of vitamin D and DHCR7 mutations are believed to be important for early humans to adapt to Northern Europe where residents have reduced ultraviolet-B exposure and tend to have light skin color. IRF4 is a key locus responsible for skin color, with a vitamin D receptor-binding interval. These vGWAS results together suggest that vitamin D deficiency is potentially causal of sero-negative RA and provide new insights into the pathogenesis of the disorder.

Replication of Associations of Genetic Loci Outside the HLA Region With Susceptibility to Anti-Cyclic Citrullinated Peptide-Negative Rheumatoid Arthritis

Objective

Genetic polymorphisms within the HLA region explain only a modest proportion of anti–cyclic citrullinated peptide (anti‐CCP)–negative rheumatoid arthritis (RA) heritability. However, few non‐HLA markers have been identified so far. This study was undertaken to replicate the associations of anti‐CCP–negative RA with non‐HLA genetic polymorphisms demonstrated in a previous study.

Methods

The Rheumatoid Arthritis Consortium International densely genotyped 186 autoimmune‐related regions in3,339 anti‐CCP–negative RA patients and 15,870 controls across 6 different populations using the Illumina ImmunoChip array. We performed a case–control replication study of the anti‐CCP–negative markers with the strongest associations in that discovery study, in an independent cohort of anti‐CCP–negative UK RA patients. Individuals from the arcOGENConsortium and Wellcome Trust Case Control Consortium were used as controls. Genotyping in cases was performed using Sequenom MassArray technology. Genome‐wide data from controls were imputed using the 1000 Genomes Phase I integrated variant call set release version 3 as a reference panel.

Results

After genotyping and imputation quality control procedures, data were available for 15 non‐HLA single‐nucleotide polymorphisms in 1,024 cases and 6,348 controls. We confirmed the known markers ANKRD55 (meta‐analysis odds ratio [OR] 0.80; P = 2.8 × 10⁻¹³)and BLK (OR 1.13; P = 7.0 × 10⁻⁶) and identified new and specific markers of anti‐CCP–negative RA (prolactin [PRL] [OR 1.13; P = 2.1 × 10⁻⁶] and NFIA [OR 0.85; P = 2.5 × 10⁻⁶]). Neither of these loci is associated with other common, complex autoimmune diseases.

Conclusion

Anti‐CCP–negative RA and anti‐CCP–positive RA are genetically different disease subsets that only partially share susceptibility factors. Genetic polymorphisms located near the PRL and NFIA genes represent examples of genetic susceptibility factors specific for anti‐CCP–negative RA.

Association Between Serum Antibodies to Periodontal Bacteria and Rheumatoid Factor in the Third National Health and Nutrition Examination Survey

OBJECTIVE

Alterations in the microbiome, including the periodontal microbiome, may be a risk factor for rheumatoid arthritis (RA). Most studies that have analyzed this association are relatively small, focus primarily on a single periodontal pathogen (Porphyromonas gingivalis), and are not population based. This study was undertaken to investigate the association between elevated serum levels of IgG antibodies to 19 periodontal species and the prevalence of rheumatoid factor (RF) in a large nationally representative sample of adults.

METHODS

The Third National Health and Nutrition Examination Survey (NHANES-III) is a cross-sectional sample of the noninstitutionalized US population (n = 33,994). Our study population included all dentate participants who were 60 years and older, did not have RA as defined by a modified version of the American College of Rheumatology 1987 criteria, and had complete data for both serum IgG antibodies against periodontal bacteria and serum RF antibody titer (n = 2,461).

RESULTS

Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) summarizing the relationship between the 19 periodontal serum IgG antibodies and RF seropositivity ranged from 0.53 (95% CI 0.29-0.97) to 1.27 (95% CI 0.79-2.06), and 17 of the 19 observed ORs were <1.0. The ORs for RF seropositivity among participants with elevated Prevotella intermedia (0.53 [95% CI 0.29-0.97]) and Capnocytophaga ochracea (0.54 [0.31-0.95]) IgG levels were statistically significant.

CONCLUSION

Our findings indicate that elevated levels of IgG antibodies to periodontal bacteria are mostly unassociated with RF seropositivity in the nationally representative NHANES-III. Elevated levels of antibodies to P intermedia and C ochracea are associated with lower odds of RF seropositivity.

MicroRNA-34a dependent regulation of AXL controls the activation of dendritic cells in inflammatory arthritis

Current treatments for rheumatoid arthritis (RA) do not reverse underlying aberrant immune function. A genetic predisposition to RA, such as HLA-DR4 positivity, indicates that dendritic cells (DC) are of crucial importance to pathogenesis by activating auto-reactive lymphocytes. Here we show that microRNA-34a provides homoeostatic control of CD1c⁺ DC activation via regulation of tyrosine kinase receptor AXL, an important inhibitory DC auto-regulator. This pathway is aberrant in CD1c⁺ DCs from patients with RA, with upregulation of miR-34a and lower levels of AXL compared to DC from healthy donors. Production of pro-inflammatory cytokines is reduced by ex vivo gene-silencing of miR-34a. miR-34a-deficient mice are resistant to collagen-induced arthritis and interaction of DCs and T cells from these mice are reduced and do not support the development of Th17 cells in vivo. Our findings therefore show that miR-34a is an epigenetic regulator of DC function that may contribute to RA.

Genetics of rheumatoid arthritis susceptibility, severity, and treatment response

A decade after the first genome-wide association study in rheumatoid arthritis (RA), a plethora of genetic association studies have been published on RA and its clinical or serological subtypes. We review the major milestones in the study of the genetic architecture of RA susceptibility, severity, and response to treatment. We set the scientific context necessary for non-geneticists to understand the potential clinical applications of human genetics and its significance for a stratified approach to the management of RA in the future.

Anti-Citrullinated Protein Antibodies Are Associated With Neutrophil Extracellular Traps in the Sputum in Relatives of Rheumatoid Arthritis Patients

OBJECTIVE

Studies suggest that rheumatoid arthritis (RA)-related autoimmunity is initiated at a mucosal site. However, the factors associated with the mucosal generation of this autoimmunity are unknown, especially in individuals who are at risk of future RA. Therefore, we tested anti-cyclic citrullinated peptide (anti-CCP) antibodies in the sputum of RA-free first-degree relatives (FDRs) of RA patients and patients with classifiable RA.

METHODS

We evaluated induced sputum and serum samples from 67 FDRs and 20 RA patients for IgA anti-CCP and IgG anti-CCP, with cutoff levels for positivity determined in a control population. Sputum was also evaluated for cell counts, neutrophil extracellular traps (NETs) using sandwich enzyme-linked immunosorbent assays for protein/nucleic acid complexes, and total citrulline.

RESULTS

Sputum was positive for IgA and/or IgG anti-CCP in 14 of 20 RA patients (70%) and 17 of 67 FDRs (25%), including a portion of FDRs who were serum anti-CCP negative. In the FDRs, elevations of sputum IgA and IgG anti-CCP were associated with elevated sputum cell counts and NET levels. IgA anti-CCP was associated with ever smoking and with elevated sputum citrulline levels.

CONCLUSION

Anti-CCP is elevated in the sputum of FDRs, including seronegative FDRs, suggesting that the lung may be a site of anti-CCP generation in this population. The association of anti-CCP with elevated cell counts and NET levels in FDRs supports a hypothesis that local airway inflammation and NET formation may drive anti-CCP production in the lung and may promote the early stages of RA development. Longitudinal studies are needed to follow the evolution of these processes relative to the development of systemic autoimmunity and articular RA.

Environmental factors and hormones in the development of rheumatoid arthritis

The etiopathogenesis of rheumatoid arthritis (RA) is partially understood. Genetic, environmental, and hormonal factors and their interactions are considered to play an important role on disease development. The relative contribution of environmental factors to RA development is probably larger than previously thought. The aim of this review is to appraise robust evidence about the role of environmental and hormonal risk factors for RA. We will discuss inhaled pollutants, nutritional habits, infectious, hormonal, and reproductive factors. As some of these factors are potentially modifiable, understanding their impact on RA development opens new opportunities for potential interventions and disease prevention.

Genetic and environmental risk factors for rheumatoid arthritis

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

Abdominal obesity, gender and the risk of rheumatoid arthritis - a nested case-control study

Background

The risk of development of rheumatoid arthritis (RA) could be affected by immune activation in obesity. Our objective was to evaluate the association between obesity in general, and abdominal obesity, and the risk for subsequent development of RA.

Methods

In two large population-based, prospective cohorts, 557 cases (mean age at RA symptom onset 58, SD 10 years, 68% women) who subsequently developed RA and 1671 matched controls were identified. From a health examination antedating symptom onset (median 5.5 years), collected data on body mass index (BMI; kg/m²), smoking habits, and educational level was used in conditional logistical regression models. Corresponding regression models were used to analyse the association between waist circumference measurements (cm) and RA development in a subset of the population.

Results

BMI and waist circumference were associated with the risk of RA development, adjusted odds ratio (OR) (95% CI), 1.13 (1.00, 1.28) per 5 kg/m², and 1.02 (1.01, 1.04) per cm, respectively. An association was also observed for obesity (BMI ≥30) OR 1.45 (1.07, 1.95), compared with BMI <25. After stratification for sex the associations were enhanced in men, and attenuated in women. Among men with BMI above normal a 3–5 times increased risk for RA disease development at 50 years of age or earlier was observed. Abdominal obesity with waist circumference >102 cm was associated with a 2–3 times increased risk of RA, but not abdominal obesity (>88 cm) in women.

Conclusions

Obesity or abdominal obesity, respectively, was independently associated with a modest increase of the risk for subsequent development of RA. This appeared to be relevant mainly for early RA disease onset among men.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1171-2) contains supplementary material, which is available to authorized users.