Impact of shared epitope genotype and ethnicity on erosive disease: a meta-analysis of 3,240 rheumatoid arthritis patients

HLA-DRB1 Is Associated with Therapeutic Responsiveness in IgG4-related Disease

Objective Glucocorticoids are key drugs used in remission induction therapy for IgG4-related disease (IgG4-RD). However, the therapeutic outcomes vary widely, with some patients requiring long-term maintenance therapy and others relapsing repeatedly, whereas still others can tolerate withdrawal. These variations underscore the need for personalized treatment strategies for IgG4-RD. We examined the relationship between human leukocyte antigen (HLA) genotypes and the response to glucocorticoid treatment in patients with IgG4-RD. Methods Eighteen IgG4-RD patients visiting our hospital were included in the study. Peripheral blood samples were collected, HLA genotypes were determined, and the response to glucocorticoid treatment (maintenance dose at the time of last observation, glucocorticoid dose when the serum IgG4 level was the lowest after remission induction therapy, and occurrence of relapse) was examined retrospectively. Results The DQB1*12:01 genotypes were associated with a prednisolone maintenance dose of <7 mg/day. A prednisolone dose ≥10 mg with a minimum serum IgG4 level was significantly more common in B*40:01 and DRB1-GB-7-Val (DRB1*04:01, *04:03, *04:05, *04:06, and *04:10) patients than other alleles. Relapse also tended to be more common in DRB1-GB-7-Val carriers than other alleles. Conclusion These data suggest that HLA-DRB1 is associated with glucocorticoid treatment responsiveness and is important for follow-up monitoring of serum IgG4 levels during glucocorticoid tapering. We believe that these data will contribute to the future development of personalized medicine for IgG4-RD.

Real-world effectiveness and safety of tofacitinib and abatacept in patients with rheumatoid arthritis

OBJECTIVE

We compared the 52-week effectiveness and safety of tofacitinib (TOF) and abatacept (ABT) in patients with RA in a real-world setting and investigated a role of human leucocyte antigens (HLA)-DRB1 shared epitope (SE) in the effectiveness.

METHODS

RA patients starting TOF (n = 187) and ABT (n = 183) were enrolled. Effectiveness was compared after reducing the selection bias to a minimum using the inverse probability of treatment weighting (IPTW) based on propensity scores. The influence of SE alleles on effectiveness was compared within each treatment group. A treatment group comparison was also performed within SE-positive and SE-negative groups.

RESULTS

Herpes zoster and some laboratory abnormalities were more frequent in the TOF group than in the ABT group. Patient characteristics did not differ significantly between treatment groups after adjustments with IPTW. The TOF group had a significantly higher proportion of DAS in 28 joints using ESR (DAS28-ESR) remission at week 52 than the ABT group. The DAS28-ESR at week 12 and thereafter was not affected by the copy number of SE alleles in the TOF group, but decreased significantly as the copy number increased in the ABT group. In SE-positive patients, remission and drug retention rates did not differ significantly between the two treatment groups. In SE-negative patients, the TOF group showed significantly higher remission and drug retention rates than the ABT group.

CONCLUSION

The present results suggest that TOF is more effective with regard to remission at week 52 based on treatment responses in SE-negative RA patients.

The Role of Shared Epitope in Rheumatoid Arthritis Prognosis in Relation to Anti-Citrullinated Protein Antibody Positivity

Introduction

Shared epitope (SE) is present in high proportions of anti-citrullinated protein antibody (ACPA) + patients with rheumatoid arthritis (RA) and is associated with poor prognosis. We assessed the role of SE in RA prognosis, in relation to ACPA positivity.

Methods

Patients enrolled in the Brigham and Women’s RA Sequential Study were included. Changes from baseline in disease activity (Disease Activity Score in 28 joints using C-reactive protein [DAS28 (CRP)], Clinical Disease Activity Index [CDAI], Simplified Disease Activity Index [SDAI]) to 1 year were assessed. Baseline characteristics were compared by SE and ACPA status (±; chi-squared, Kruskal-Wallis). Association between number of SE alleles and ACPA status (logistic regression models), relationships between baseline characteristics and changes in disease activity (adjusted linear regression model), and effect of ACPA on the association between SE and changes in disease activity (mediation analysis) were studied.

Results

Nine hundred twenty-six patients were included. SE + versus SE − patients had significantly longer disease duration and higher disease activity scores and were more likely to have erosive disease, have higher comorbidity burden, and be RF + (all p < 0.05). Among patients with one or two SE alleles (vs. 0), odds of being ACPA + were 1.97 (p = 0.0003) and 3.82 (p < 0.0001), respectively. SE + versus SE − patients had worse disease activity scores as indicated by mean increases in DAS28 (CRP) of 0.22, CDAI of 2.07, and SDAI of 2.43 over 1 year (all p < 0.05). Direct effect of SE + accounted for 76.4–80.1% of total effect in disease activity increases.

Conclusions

SE is strongly associated with ACPA positivity and higher disease activity in patients with RA. SE was associated with greater increases in disease activity over 1 year, which was partially mediated by the presence of ACPA.

Trial Registration

ClinicalTrials.gov identifier: NCT01793103; registration date: February 15, 2013, retrospectively registered.

Patients with rheumatoid arthritis (RA) experience inflamed and damaged joints. RA is an autoimmune disease where proteins called autoantibodies in the blood of patients with RA target the patient’s own joint tissue and organs by mistake. This causes inflammation. Patients with certain autoantibodies, such as anti-citrullinated protein antibodies (ACPAs), may experience worse symptoms. There are certain genetic risk factors that may mean a person is more likely to develop RA. One example of a genetic risk factor is having the shared epitope (SE).

Our study looked at almost 1000 patients with RA in the general population. It explored the impact of having SE and ACPAs on changes in RA disease activity. Patients with SE had RA for a longer time, had more severe disease, and were more likely to have other diseases compared with patients without SE. Patients with SE were also more likely to have ACPAs. Over the course of one year, patients with SE had larger increases in RA disease activity than those patients without SE, even though they were taking the same treatments. These results suggest that patients with the genetic risk factor, SE often have RA that is harder to treat. Doctors should take this into account when selecting treatment for RA.

Association of rheumatoid arthritis and its severity with human leukocytic antigen-DRB1 alleles in Kurdish region in North of Iraq

BACKGROUND

Rheumatoid arthritis is a complex multifactorial chronic disease, the importance of human leukocytic antigen (HLA) as a major genetic risk factor for rheumatoid arthritis was studied worldwide. The objective of this study is to identify the association of HLA-DRB1 subtypes with rheumatoid arthritis and its severity in Kurdish region.

METHODS

A case-control study recruited 65 rheumatoid arthritis patients and 100 healthy individuals as control group all over the Kurdistan region/Iraq. Both patient and control groups are genotyped using polymerase chain reaction with sequence specific primer. Anti-CCP antibodies were measured by ELISA test. Rheumatoid factor, C-reactive protein, and disease activity score 28 which measured by DAS-28 values were calculated. The DAS-28 was used to assess the clinical severity of the patients.

RESULTS

HLA-DRB1-0404 and HLA-DRB1-0405 frequencies showed a strong association with disease susceptibility (P < 0.001). The frequency of HLA-DRB1-0411 and HLA-DRB1-0413 were significantly higher in control group (P < 0.001). The frequency of rheumatoid factor and Anti-CCP were significantly higher among shared epitope-positive patients compared to shared epitope-negative patients (P < 0.001). Regarding the disease activity by DAS-28, rheumatoid arthritis patients didn't show significant difference between the shared epitope-positive and shared epitope-negative patients.

CONCLUSIONS

HLA-DR0404 and HLA-DR0405 alleles are related to RA, while HLA-DR1-0411 and HLA-DRB1-0413 protect against RA in the Kurdistan region in the North of Iraq.

Etiology and Risk Factors for Rheumatoid Arthritis: A State-of-the-Art Review

Rheumatoid arthritis (RA) is the most common systemic inflammatory rheumatic disease. It is associated with significant burden at the patient and societal level. Extensive efforts have been devoted to identifying a potential cause for the development of RA. Epidemiological studies have thoroughly investigated the association of several factors with the risk and course of RA. Although a precise etiology remains elusive, the current understanding is that RA is a multifactorial disease, wherein complex interactions between host and environmental factors determine the overall risk of disease susceptibility, persistence and severity. Risk factors related to the host that have been associated with RA development may be divided into genetic; epigenetic; hormonal, reproductive and neuroendocrine; and comorbid host factors. In turn, environmental risk factors include smoking and other airborne exposures; microbiota and infectious agents; diet; and socioeconomic factors. In the present narrative review, aimed at clinicians and researchers in the field of RA, we provide a state-of-the-art overview of the current knowledge on this topic, focusing on recent progresses that have improved our comprehension of disease risk and development.

Are There Any Ethnic Differences in the Response to Baricitinib for the Treatment of Rheumatoid Arthritis?

Introduction Baricitinib is an oral synthetic Janus Kinase inhibitor that inhibits JAK1 and JAK2, and the new kid on the block in the treatment of rheumatoid arthritis (RA). To date, there are no studies comparing the clinical benefit of baricitinib in RA between different ethnicities. Ethnicity plays a role in the effectiveness of therapeutic agents. Given the large multi-ethnic population of Leicestershire in the United Kingdom and the range of new therapeutics in RA, we reviewed our cohort of patients with RA to see whether there is any difference in baricitinib Disease Activity Score 28 (DAS28) response between the Asian and White cohorts. Methods This was a retrospective study. The patients included were those under the care of rheumatology at University Hospitals of Leicester (UHL) with a diagnosis of RA and either receiving baricitinib or had received it in the past. Data was collected using the UHL information technology systems, clinic letters and pharmacy records. In addition to ethnicity, we reviewed patient age, gender, concurrent disease-modifying anti-rheumatic drugs (DMARDs) used, previous biologics used, baseline and post-treatment DAS28, dropout from therapy, baseline biochemical assays (anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) status) and radiographic findings. An independent t-test was used to compare continuous data, and Pearson's chi-squared test was used to compare categorical data. Results A total of 120 patients were included in the analysis, and data were analysed with Portable Format for Analytics (PFA). There was no statistically significant difference in the mean DAS28 at baseline (Asian: 5.17 versus White: 4.65; p-value = 0.107) and post-treatment (Asian: 2.8 versus White: 3.3; p-value = 0.404). Comparing both ethnicities, there was no statistically significant difference in previous biologics used, anti-CCP and RF titres, and radiographic findings of erosions. Conclusion This is the first study of its kind, and it found no significant difference in baricitinib response between the Asian and White cohorts. Our study had certain limitations, and future studies will be needed to evaluate this subject further. Such data is important as it can contribute to a body of evidence that may in the future help inform clinical decision-making.

Causal risk and protective factors in rheumatoid arthritis: A genetic update

The characterization of risk and protective factors in complex diseases such as rheumatoid arthritis (RA) has evolved from epidemiological studies, which test association, to the use of Mendelian randomization approaches, which test direct relationships. Indeed, direct associations with the mucosal origin of RA are retrieved with periodontal disease (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans predominantly), interstitial lung involvement, tobacco smoking and air pollutants. Next, factors directly associated with an acquired immune response include genetic factors (HLA DRB1, PTPN22), capacity to produce anti-modified protein antibodies (AMPA), and relatives with a history of autoimmune diseases. Finally, factors can be also classified according to their direct capacity to interfere with the IL-6/CRP/sIL-IL6R proinflammatory pathway as risk factor (body fat, cardiometabolic factors, type 2 diabetes, depressive syndrome) or either as protective factors by controlling of sIL-6R levels (higher education level, and intelligence). Although some co-founders have been characterized (e.g. vitamin D, physical activity, cancer) the direct association with sex-discrepancy, pregnancy, and infections among other factors remains to be better explored.

Impact of the HLA-DRB1 shared epitope on responses to treatment with tofacitinib or abatacept in patients with rheumatoid arthritis

Objectives

The aim of this study was to compare the clinical effectiveness of tofacitinib and abatacept and clarify the impact of the HLA-DRB1 shared epitope (SE) on responses to these treatments in patients with rheumatoid arthritis (RA).

Methods

After adjustments by propensity score matching, 70 out of 161 patients receiving tofacitinib and 70 out of 131 receiving abatacept were extracted. The clinical effectiveness of both drugs over 24 weeks and the impact of the copy numbers of SE on effectiveness outcomes were investigated.

Results

The percentage of patients in remission in the 28-joint count disease activity score using the erythrocyte sedimentation rate (DAS28-ESR) did not significantly differ between patients receiving tofacitinib and abatacept at week 24 (32% vs 37%, p = 0.359). The mean change at week 4 in DAS28-ESR from baseline was significantly greater in patients receiving tofacitinib than in those receiving abatacept (− 1.516 vs − 0.827, p = 0.0003). The percentage of patients in remission at week 4 was 30% with tofacitinib and 15% with abatacept (p = 0.016). When patients were stratified by the copy numbers of SE alleles, differences in these numbers did not affect DAS28-ESR scores of patients receiving tofacitinib. However, among patients receiving abatacept, DAS28-ESR scores were significantly lower in patients carrying 2 copies of SE alleles than in those carrying 0 copies at each time point throughout the 24-week period. Furthermore, the percentage of patients in remission with DAS28-ESR at week 24 was not affected by the copy numbers of SE alleles in patients receiving tofacitinib (p = 0.947), whereas it significantly increased as the copy numbers became higher in patients receiving abatacept (p = 0.00309). Multivariable logistic regression analyses showed a correlation between the presence of SE and DAS28-ESR remission in patients receiving abatacept (OR = 25.881, 95% CI = 3.140–213.351, p = 0.0025), but not in those receiving tofacitinib (OR = 1.473, 95% CI = 0.291–7.446, p = 0.639).

Conclusions

Although the clinical effectiveness of tofacitinib and abatacept was similar at week 24, tofacitinib was superior to abatacept for changes from baseline in DAS28-ESR and the achievement of remission at week 4. SE positivity was associated with the achievement of DAS28-ESR remission by week 24 in patients receiving abatacept, but not in those receiving tofacitinib.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02612-w.

First Asian case of biopsy-confirmed manubriosternal joint involvement in rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory polyarthritis that typically affects the small joints but can also involve the manubriosternal joint (MSJ). Although cases of MSJ involvement in RA are rare, such cases present with chest pain, a mass-like lesion, and subluxation. These cases can also be diagnosed incidentally, while patients are asymptomatic. It is important to differentiate RA involving the MSJ from other diseases such as ankylosing spondylitis that can affect the MSJ. Several cases of RA affecting the MSJ have been reported in Western countries, but none have been reported to date in Asia, especially with disease activity of RA. Here, we report a case of RA in the MSJ that was confirmed by imaging and histological investigation in a middle-aged Asian woman.

FcγRIIIA-mediated activation of NK cells by IgG heavy chain complexed with MHC class II molecules

Natural killer (NK) cells are a major FcγRIIIA-expressing lymphocyte population that mediate antibody-dependent cellular cytotoxicity. Although NK cells are critical for immunity against viruses and tumors, they are also activated in the joints of patients with rheumatoid arthritis (RA) and may be involved in disease progression. We previously found that human leukocyte antigen (HLA) class II molecules transport misfolded cellular proteins, such as IgG heavy chain (IgGH), to the cell surface via association with their peptide-binding grooves. Furthermore, we found that IgGHs bound to HLA class II molecules encoded by RA susceptibility alleles are specific targets for rheumatoid factor, an auto-antibody involved in RA. Here, we report that IgGHs bound to HLA class II molecules preferentially stimulate FcγRIIIA-expressing but not FcγRI-expressing cells. A significant correlation was observed between the reactivity of FcγRIIIA-expressing cells to IgGH complexed with a specific HLA-DR allele and the odds ratio for HLA-DR allele's association with RA. Moreover, primary human NK cells expressing FcγRIIIA demonstrated IFN-γ production and cytotoxicity against cells expressing IgGH complexed with HLA class II molecules. Our findings suggest that IgGH complexed with HLA class II molecules are involved in the activation of FcγRIIIA-expressing NK cells observed within arthritic joints.

Local transplantation of adipose-derived stem cells has a significant therapeutic effect in a mouse model of rheumatoid arthritis

Adipose-derived stem cells (ADSCs) have anti-inflammatory and regenerative properties. The purpose of this study was to investigate the effect of locally administered ADSCs in a rheumatoid arthritis (RA) mouse model. In an in vivo experiment, single-cell ADSCs and three dimensionally-cultured ADSC spheroids were injected intra-articularly into the knees of RA model mice and histologically assessed. Marked improvement of synovial inflammation and articular cartilage regeneration was found in ADSC-treated mice. Proliferation, migration, and apoptosis assays of synovial fibroblasts incubated with single-cell and spheroid ADSCs were performed. The expression levels of total cytokine RNA in ADSC single cells, spheroids, and ADSC-treated inflammatory synovial fibroblasts were also evaluated by quantitative reverse transcription PCR. ADSCs suppressed the proliferation and migration of activated inflammatory cells and downregulated inflammatory cytokines. TSG-6 and TGFβ1 were significantly upregulated in ADSCs compared to controls and TGFβ1 was significantly upregulated in ADSC spheroids compared to single cells. The apoptosis rate of ADSC spheroids was significantly lower than that of single-cell ADSCs. These results indicated that intra-articular administration of ADSC single cells and spheroids was effective in an RA mouse model, offering a novel approach for the development of effective localized treatments for patients with RA.

Genetic associations with radiological damage in rheumatoid arthritis: Meta-analysis of seven genome-wide association studies of 2,775 cases

BACKGROUND

Previous studies of radiological damage in rheumatoid arthritis (RA) have used candidate-gene approaches, or evaluated single genome-wide association studies (GWAS). We undertook the first meta-analysis of GWAS of RA radiological damage to: (1) identify novel genetic loci for this trait; and (2) test previously validated variants.

METHODS

Seven GWAS (2,775 RA cases, of a range of ancestries) were combined in a meta-analysis. Radiological damage was assessed using modified Larsen scores, Sharp van Der Heijde scores, and erosive status. Single nucleotide polymophsim (SNP) associations with radiological damage were tested at a single time-point using regression models. Primary analyses included age and disease duration as covariates. Secondary analyses also included rheumatoid factor (RF). Meta-analyses were undertaken in trans-ethnic and European-only cases.

RESULTS

In the trans-ethnic primary meta-analysis, one SNP (rs112112734) in close proximity to HLA-DRB1, and strong linkage disequilibrium with the shared-epitope, attained genome-wide significance (P = 4.2x10-8). In the secondary analysis (adjusting for RF) the association was less significant (P = 1.7x10-6). In both trans-ethnic primary and secondary meta-analyses 14 regions contained SNPs with associations reaching P<5x10-6; in the European primary and secondary analyses 13 and 10 regions contained SNPs reaching P<5x10-6, respectively. Of the previously validated SNPs for radiological progression, only rs660895 (tagging HLA-DRB1*04:01) attained significance (P = 1.6x10-5) and had a consistent direction of effect across GWAS.

CONCLUSIONS

Our meta-analysis confirms the known association between the HLA-DRB1 shared epitope and RA radiological damage. The lack of replication of previously validated non-HLA markers highlights a requirement for further research to deliver clinically-useful prognostic genetic markers.

HLA-DRB1 Haplotypes, Shared Epitope, and Disease Outcomes in US Veterans with Rheumatoid Arthritis

OBJECTIVE

To evaluate associations of HLA-DRB1 haplotypes and shared epitope (SE) with rheumatoid arthritis (RA) severity and all-cause mortality in RA.

METHODS

Patients with RA from the Veterans Affairs Rheumatoid Arthritis (VARA) registry were followed from enrollment until death or December 31, 2013. Clinical characteristics, DNA, and serum were collected at enrollment. Radiographic damage, the presence or absence of subcutaneous nodules, disease activity measures, and functional status were assessed at enrollment and updated during followup. Sixteen HLA-DRB1 haplotypes and SE status were determined from banked DNA. Associations between HLA-DRB1 haplotypes, RA disease characteristics, and mortality were assessed in multivariable regression models.

RESULTS

Within VARA, 1443 participants had genotyping and accrued 6150 patient-years of followup. Haplotypes VKA, VRA, LRA, SRA, SRE, SKR, and SEA, and SE alleles were significantly associated with seropositivity for rheumatoid factor (RF) and/or anticyclic citrullinated peptide (anti-CCP). Haplotypes VKA and SKR were associated with higher RF concentrations, while VRA, DRE, and GRQ were associated with lower RF concentrations. Haplotypes VKA, VRA, and LRA were associated with higher concentrations of anti-CCP antibody, while haplotypes SRA, SRE, LEA, SKR, and SEA were significantly associated with lower anti-CCP concentrations. Haplotype VKA (OR 1.39, 95% CI 1.08-1.80) was associated with increased frequency of radiographic damage at enrollment but none of the haplotypes were associated with the presence of subcutaneous nodules. Haplotypes SKA (HR 1.52, 95% CI 1.26-1.83) was associated with higher mortality.

CONCLUSION

HLA-DRB1 haplotypes are independently and variably associated with seropositivity, autoantibody concentrations, and outcomes in RA.

HLA-DRB1 Analysis Identified a Genetically Unique Subset within Rheumatoid Arthritis and Distinct Genetic Background of Rheumatoid Factor Levels from Anticyclic Citrullinated Peptide Antibodies

OBJECTIVE

HLA-DRB1 is the most important locus associated with rheumatoid arthritis (RA) and anticitrullinated protein antibodies (ACPA). However, fluctuations of rheumatoid factor (RF) over the disease course have made it difficult to define fine subgroups according to consistent RF positivity for the analyses of genetic background and the levels of RF.

METHODS

A total of 2873 patients with RA and 2008 healthy controls were recruited. We genotyped HLA-DRB1 alleles for the participants and collected consecutive data of RF in the case subjects. In addition to RF+ and RF- subsets, we classified the RF+ subjects into group 1 (constant RF+) and group 2 (seroconversion). We compared HLA-DRB1 alleles between the RA subsets and controls and performed linear regression analysis to identify HLA-DRB1 alleles associated with maximal RF levels. Omnibus tests were conducted to assess important amino acid positions.

RESULTS

RF positivity was 88%, and 1372 and 970 RF+ subjects were classified into groups 1 and 2, respectively. RF+ and RF- showed similar genetic associations to ACPA+ and ACPA- RA, respectively. We found that shared epitope (SE) was more enriched in group 2 than 1, p = 2.0 × 10^-5, and that amino acid position 11 showed a significant association between 1 and 2, p = 2.7 × 10^-5. These associations were independent of ACPA positivity. SE showed a tendency to be negatively correlated with RF titer (p = 0.012). HLA-DRB1*09:01, which reduces ACPA titer, was not associated with RF levels (p = 0.70).

CONCLUSION

The seroconversion group was shown to have distinct genetic characteristics. The genetic architecture of RF levels is different from that of ACPA.

Genetic and environmental risk factors for rheumatoid arthritis in a UK African ancestry population: the GENRA case-control study

Objectives

To evaluate whether genetic and environmental factors associated with RA in European and Asian ancestry populations are also associated with RA in African ancestry individuals.

Methods

A case-control study was undertaken in 197 RA cases and 868 controls of African ancestry (Black African, Black Caribbean or Black British ethnicity) from South London. Smoking and alcohol consumption data at RA diagnosis was captured. Genotyping was undertaken (Multi-Ethnic Genotyping Array) and human leukocyte antigen (HLA) alleles imputed. The following European/Asian RA susceptibility factors were tested: 99 genome-wide loci combined into a genetic risk score; HLA region [20 haplotypes; shared epitope (SE)]; smoking; and alcohol consumption. The SE was tested for its association with radiological erosions. Logistic regression models were used, including ancestry-informative principal components, to control for admixture.

Results

European/Asian susceptibility loci were associated with RA in African ancestry individuals. The genetic risk score provided an odds ratio (OR) for RA of 1.53 (95% CI: 1.31, 1.79; P = 1.3 × 10 - 7 ). HLA haplotype ORs in European and African ancestry individuals were highly correlated ( r = 0.83, 95% CI: 0.56, 0.94; P = 1.1 × 10 - 4 ). Ever-smoking increased (OR = 2.36, 95% CI: 1.46, 3.82; P = 4.6 × 10 - 4 ) and drinking alcohol reduced (OR = 0.34, 95% CI: 0.20, 0.56; P = 2.7 × 10 - 5 ) RA risk in African ancestry individuals. The SE was associated with erosions (OR = 2.61, 95% CI: 1.36, 5.01; P = 3.9 × 10 - 3 ).

Conclusion

Gene-environment RA risk factors identified in European/Asian ancestry populations are relevant in African ancestry individuals. As modern statistical methods facilitate analysing ancestrally diverse populations, future genetic studies should incorporate African ancestry individuals to ensure their implications for precision medicine are universally applicable.

Human Leukocyte Antigen Shared Epitope and Inflammation, Cardiovascular Disease, Cancer, and Mortality Among Postmenopausal Women in the Women's Health Initiative Rheumatoid Arthritis Study

Specific alleles of the human leukocyte antigen (HLA)-DRB1 gene (HLA-DRB1) encode a "shared epitope" (SE) associated with rheumatoid arthritis (RA), especially more severe cyclic-citrullinated peptide antibody-positive (anti-CCP+) RA. We evaluated associations of number of SE alleles (0, 1, or 2) with total and cardiovascular disease (CVD) mortality and incident coronary heart disease (CHD), CVD, and cancer over a mean 8.9 (standard deviation, 3.5) years of follow-up, stratifying by baseline anti-CCP status (positive (+) vs. negative (-)). A longitudinal study, the Women's Health Initiative RA Study (1993-2010), sampled postmenopausal women who reported RA at baseline (1993-1998) or follow-up in the Women's Health Initiative, classified as anti-CCP+ RA (n = 556) or anti-CCP- non-RA (n = 1,070). Among anti-CCP+ RA women, SE alleles were not related to age-adjusted risks of CHD, CVD, or cancer or to total or CVD mortality. Among anti-CCP- non-RA women, age-adjusted hazard ratios for 1 and 2 SE alleles versus 0 SE alleles were 0.41 (95% confidence interval (CI): 0.34, 0.50) and 0.44 (95% CI: 0.27, 0.72), respectively, for CVD; 0.43 (95% CI: 0.37, 0.53) and 0.30 (95% CI: 0.16, 0.64), respectively, for CHD; and 0.62 (95% CI: 0.53, 0.73) and 0.52 (95% CI: 0.33, 0.83), respectively, for cancer. Associations persisted after adjustment for CVD risk factors, joint pain, rheumatoid factor positivity, and inflammatory markers (white blood cell count or cytokine level). In future studies, investigators should evaluate SE associations among anti-CCP- adults without RA and potential mechanisms.

Dense Genotyping of Immune-Related Regions Identifies Loci for Rheumatoid Arthritis Risk and Damage in African Americans

Over 100 risk loci for rheumatoid arthritis (RA) have been identified in individuals of European and Asian descent, but the genetic basis for RA in African Americans is less well understood. We genotyped 610 African Americans with autoantibody positive RA and 933 African American controls on the ImmunoChip (iChip) array. Using multivariable regression we evaluated the association between iChip markers and the risk of RA and radiographic severity. The single nucleotide polymorphism (SNP) rs1964995 (OR = 1.97, p = 1.28 × 10^-15) near HLA-DRB1 was the most strongly associated risk SNP for RA susceptibility; SNPs in AFF3, TNFSF11, and TNFSF18 loci were suggestively associated (10^-4 < p < 3.1 × 10^-6). Trans-ethnic fine mapping of AFF3 identified a 90% credible set containing previously studied variants including rs9653442, rs7608424, and rs6712515 as well as the novel candidate variant rs11681966; several of these likely influence AFF3 gene expression level. Variants in TNFRSF9, CTLA4, IL2RA, C5/TRAF1, and ETS1 - but no variants within the major histocompatibility complex - were associated with RA radiographic severity. Conditional regression and pairwise linkage disequilibrium (LD) analyses suggest that additional pathogenic variants may be found in ETS1 and IL2RA beyond those found in other ethnicities. In summary, we use the dense genotyping of the iChip array and unique LD structure of African Americans to validate known risk loci for RA susceptibility and radiographic severity, and to better characterize the associations of AFF3, ETS1, and IL2RA.

Immunophenotyping of rheumatoid arthritis reveals a linkage between HLA-DRB1 genotype, CXCR4 expression on memory CD4(+) T cells, and disease activity

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease that leads to destructive arthritis. Although the HLA class II locus is the strongest genetic risk factor for rheumatoid arthritis, the relationship between HLA class II alleles and lymphocyte activation remains unclear. We performed immunophenotyping of peripheral blood mononuclear cells on 91 HLA-DRB1-genotyped RA patients and 110 healthy donors. The frequency of memory CXCR4⁺CD4⁺ T cells, and not Th1 and Th17 cells, was significantly associated with disease severity by multiple linear regression analysis. RA patients with one or more susceptible HLA-DR haplotypes (shared epitope: SE) displayed a significantly higher frequency of memory CXCR4⁺CD4⁺ T cells. Moreover, the frequency of memory CXCR4⁺CD4⁺ T cells significantly correlated with the expression level of HLA-DR on B cells, which was elevated in RA patients with SE. In vitro analysis and transcriptomic pathway analysis suggested that the interaction between HLA-DR and T cell receptors is an important regulator of memory CXCR4⁺CD4⁺ T cells. Clinically, a higher frequency of memory CXCR4⁺CD4⁺ T cells predicted a better response to CTLA4-Ig. Memory CXCR4⁺CD4⁺ T cells may serve as a powerful biomarker for unraveling the linkage between HLA-DRB1 genotype and disease activity in RA.

Predictors of remission, erosive disease and radiographic progression in a Colombian cohort of early onset rheumatoid arthritis: a 3-year follow-up study

The objective of the study is to find predictors of remission, radiographic progression (RP), and erosive disease in a cohort of patients with early onset rheumatoid arthritis (EORA) that followed a therapeutic protocol aiming at remission, in a real world tight-control setting. EORA patients were enrolled in a 3-year follow-up study. Clinical, biological, immunogenetic, and radiographical data were analyzed. Radiographs were scored according to Sharp-van der Heijde (SvdH) method. RP was defined by an increase of 3 units in 36 months. Remission was defined as DAS28 <2.6. A stepwise multiple logistic regression model was used to identify independent predictors of the three target outcomes. One hundred twenty-nine patients were included. Baseline disease activity was high. Significant overall improvement was observed, but only 33.3 % achieved remission. At 36 month, 50.4 % (65) of patients showed erosions. RP was observed in 62.7 % (81) of cases. Statistical analysis showed that baseline SvdH score was the only predictive factor associated with the three outcomes evaluated. Lower HAQ-DI and absence of autoantibodies were predictive of remission. Higher levels of ESR and presence of erosions at entry were predictive of RP. Independent baseline predictors of incident erosive disease were anti-CCP and RF positivity, symptom duration at baseline >3 months, and presence of HLA-DRB1 shared epitope. Radiographic damage at baseline was the main predictor of outcomes. Autoantibodies, HAQ and ESR at baseline, symptom duration before diagnosis, and HLA-DRB1 status had influence on clinical course and development of structural joint damage in Colombian RA patients.

Epidemiology of Rheumatoid Arthritis in Southern Albania

OBJECTIVES

The aim of this study was to assess the prevalence, incidence and the burden of rheumatoid arthritis (RA) in the Southern Albania.

MATERIAL AND METHODS

This is an epidemiologic observational study with cross-sectional analyses of all patients with RA who lived in Southern Albania during the 1995-2011 years. The RA prevalence, incidence and disability-adjusted life years (DALY) were assessed.

RESULTS

During the 1995-2011 years, 194 patients (154 females and 40 males) with RA living in Southern Albania were identified. The prevalence of RA in 2011 was 0.25% in general population and 0.34% in adult (>14 years) population. The incidence of RA in 2011 was 0.012% (12 new cases per 100000 inhabitants) and 0.016% (16 new cases per 100000 adults). The prevalence increased (from 0.036% in 1996 to 0.25% in 2011) and the incidence did not change over the study period. The mortality was 3.2% (n=7 deaths). The DALY due to RA was 823 years per 100000 inhabitants during 1995-2011 years.

CONCLUSION

RA in Southern Albania has a prevalence of 0.25 % and an annual incidence of 0.012% in the general population in 2011. RA was responsible for a considerable burden on the health of population during the 1995-2011 years.

Travel- and immigration-related problems in rheumatology

Health problems are self-reported by up to 64% of travellers to the developing world. Traditionally, rheumatic symptoms are accorded little significance, but many travellers do return home with musculoskeletal complaints. The assessment of these patients is often hindered by the Western clinician's lack of familiarity with the types of infections that the patient may have encountered while travelling. Standard serological tests for autoimmune diseases can be unreliable in the setting of concomitant tropical infection, and these infections themselves can have musculoskeletal manifestations. Even in the absence of tropical infection, laboratory investigation of musculoskeletal symptoms in individuals of different ethnicities is challenging due to genetic and physiological variation. This review focusses on addressing the impact global migration has had on rheumatological clinical practice.

Do Genetic Susceptibility Variants Associate with Disease Severity in Early Active Rheumatoid Arthritis?

OBJECTIVE

Genetic variants affect both the development and severity of rheumatoid arthritis (RA). Recent studies have expanded the number of RA susceptibility variants. We tested the hypothesis that these associated with disease severity in a clinical trial cohort of patients with early, active RA.

METHODS

We evaluated 524 patients with RA enrolled in the Combination Anti-Rheumatic Drugs in Early RA (CARDERA) trials. We tested validated susceptibility variants - 69 single-nucleotide polymorphisms (SNP), 15 HLA-DRB1 alleles, and amino acid polymorphisms in 6 HLA molecule positions - for their associations with progression in Larsen scoring, 28-joint Disease Activity Scores, and Health Assessment Questionnaire (HAQ) scores over 2 years using linear mixed-effects and latent growth curve models.

RESULTS

HLA variants were associated with joint destruction. The *04:01 SNP (rs660895, p = 0.0003), *04:01 allele (p = 0.0002), and HLA-DRβ1 amino acids histidine at position 13 (p = 0.0005) and valine at position 11 (p = 0.0012) significantly associated with radiological progression. This association was only significant in anticitrullinated protein antibody (ACPA)-positive patients, suggesting that while their effects were not mediated by ACPA, they only predicted joint damage in ACPA-positive RA. Non-HLA variants did not associate with radiograph damage (assessed individually and cumulatively as a weighted genetic risk score). Two SNP - rs11889341 (STAT4, p = 0.0001) and rs653178 (SH2B3-PTPN11, p = 0.0004) - associated with HAQ scores over 6-24 months.

CONCLUSION

HLA susceptibility variants play an important role in determining radiological progression in early, active ACPA-positive RA. Genome-wide and HLA-wide analyses across large populations are required to better characterize the genetic architecture of radiological progression in RA.

Atherosclerosis in rheumatoid arthritis: is it all about inflammation?

Rheumatoid arthritis (RA) has long been associated with increased cardiovascular risk, but despite substantial improvements in disease management, mortality remains high. Atherosclerosis is more prevalent in RA than in the general population, and atherosclerotic lesions progress at a faster rate and might be more prone to rupture, causing clinical events. Cells and cytokines implicated in RA pathogenesis are also involved in the development and progression of atherosclerosis, which is generally recognized as an inflammatory condition. The two diseases also share genetic and environmental risk factors, which suggests that patients who develop RA might also be predisposed to developing cardiovascular disease. In RA, inflammation and atherosclerosis are closely linked. Inflammation mediates its effects on atherosclerosis both through modulation of traditional risk factors and by directly affecting the vessel wall. Treatments such as TNF inhibitors might have a beneficial effect on cardiovascular risk. However, whether this benefit is attributable to effective control of inflammation or whether targeting specific cytokines, implicated in atherosclerosis, provides additional risk reduction is unclear. Further knowledge of the predictors of cardiovascular risk, the effects of early control of inflammation and of drug-specific effects are likely to improve the recognition and management of cardiovascular risk in patients with RA.

Characterization of cumulative joint damage patterns in patients with rheumatoid arthritis: a clinical, serological, and gene polymorphism perspective

OBJECTIVE

To characterize cumulative joint damage (CJD) patterns in rheumatoid arthritis (RA) and determine their associations with demographic/clinical features and HLA-DRB1 gene polymorphism.

METHODS

Hand and foot radiographs were obtained from 404 patients with RA. CJD patterns were determined by 3 derivations from Sharp/van der Heijde scores, obtained by the mathematical division of scores for hands/feet (Sharp-h/f score), fingers/wrists (Sharp-f/w score), and erosion/space narrowing (Sharp-e/sn score), respectively. DNA and serum were obtained for determination of HLA-DRB1 polymorphism, rheumatoid factor (RF), and anticitrullinated protein antibodies (ACPA).

RESULTS

Patients with wrist-dominant CJD pattern were more likely to have severe RA than those with finger-dominant pattern (68.4% vs 46.0%; p = 0.036) as were those with foot-dominant vs hand-dominant CJD pattern (76.5% vs 56.4%; p = 0.044). HLA-DRB1 shared epitope (SE) alleles were associated with erosion-dominant CJD pattern (p = 0.021). Patients with erosion-dominant CJD pattern had higher levels of RF and ACPA than those with space-narrowing-dominant CJD pattern (median RF 71.35 U/ml vs 22.05 U/ml, respectively; p = 0.003; median ACPA 187.9 U/ml vs 143.2 U/ml, respectively; p < 0.001). The majority of triple-positive patients (SE+, RF+, ACPA+) had erosion-dominant CJD pattern (62.3%) while the majority of triple-negative patients (SE-, FR-, ACPA-) had space narrowing-dominant CJD pattern (75%; p = 0.017). ACPA was associated with HLA-DRB1 SE alleles (p < 0.05). Patients with foot-dominant CJD pattern were taller than those with hand-dominant CJD pattern (p = 0.002); those with erosion-dominant CJD pattern had higher weight and body mass index than those with space narrowing-dominant CJD pattern (p = 0.014, p = 0.001).

CONCLUSION

CJD patterns were associated with disease severity, HLA-DRB1 SE status, presence and titer of ACPA and RF, and morphometric features.

The multifaceted aspects of interstitial lung disease in rheumatoid arthritis

Interstitial lung disease (ILD) is a relevant extra-articular manifestation of rheumatoid arthritis (RA) that may occur either in early stages or as a complication of long-standing disease. RA related ILD (RA-ILD) significantly influences the quoad vitam prognosis of these patients. Several histopathological patterns of RA-ILD have been described: usual interstitial pneumonia (UIP) is the most frequent one, followed by nonspecific interstitial pneumonia (NSIP); other patterns are less commonly observed. Several factors have been associated with an increased risk of developing RA-ILD. The genetic background plays a fundamental but not sufficient role; smoking is an independent predictor of ILD, and a correlation with the presence of rheumatoid factor and anti-cyclic citrullinated peptide antibodies has also been reported. Moreover, both exnovo occurrence and progression of ILD have been related to drug therapies that are commonly prescribed in RA, such as methotrexate, leflunomide, anti-TNF alpha agents, and rituximab. A greater understanding of the disease process is necessary in order to improve the therapeutic approach to ILD and RA itself and to reduce the burden of this severe extra-articular manifestation.

Distribution of HLA-DRβ1 alleles among well-characterized rheumatoid arthritis patients from Western India

An association between human leukocyte antigen-DRβ1*04 and rheumatoid arthritis (RA) has been known for more than 25 years. It has been observed in many different populations, and it accounts for approximately one-third of the genetic component of RA susceptibility. Our aim was to study the distribution of HLA-DRβ1 alleles in well-characterized RA patients from Western India. Polymerase chain reaction-based sequence-specific oligonucleotide probing (PCR-SSOP) technique was used to identify HLA-DRβ1 alleles among 80 clinically well-defined patients and 90 normal controls from same ethnicity. A significant increase in the frequency of DRβ1*04 was observed among RA patients (PF% 30 vs. 7.7, OR 4.959, p value 0.00018), whereas DRβ1*03 and *14 were significantly decreased among patients when compared with controls (DRβ1*03, PF% 8.75 vs. 26.6, OR 0.2637, p value 0.00253; DRβ1*14, PF% 17.5 vs. 30.0, OR 0.4949, p value 0.05722). Our results suggest that DRβ1*04 was strongly associated with well-characterized RA patients from Western India, whereas DRβ1*03 and *14 may be protective alleles for RA. The identification of susceptible allele in patients with RA may help physician to make early decisions regarding initiation of early intensive therapy with disease modifying anti-rheumatic drugs and biological agents to decrease disability in RA patients.

PADI4 and HLA-DRB1 are genetic risks for radiographic progression in RA patients, independent of ACPA status: results from the IORRA cohort study

Introduction

Rheumatoid arthritis (RA) is a systemic, chronic inflammatory disease influenced by both genetic and environmental factors, leading to joint destruction and functional impairment. Recently, a large-scaled GWAS meta-analysis using more than 37,000 Japanese samples were conducted and 13 RA susceptibility loci were identified. However, it is not clear whether these loci have significant impact on joint destruction or not. This is the first study focused on the 13 loci to investigate independent genetic risk factors for radiographic progression in the first five years from onset of RA.

Methods

Sharp/van der Heijde score of hands at 5-year disease duration, which represents joint damage, were measured retrospectively and used as an outcome variable in 865 Japanese RA patients. Genetic factors regarded as putative risk factors were RA-susceptible polymorphisms identified by the Japanese GWAS meta-analysis, including HLA-DRB1 (shared epitope, SE), rs2240340 (PADI4), rs2230926 (TNFAIP3), rs3093024 (CCR6), rs11900673 (B3GNT2), rs2867461 (ANXA3), rs657075 (CSF2), rs12529514 (CD83), rs2233434 (NFKBIE), rs10821944 (ARID5B), rs3781913 (PDE2A-ARAP1), rs2841277 (PLD4) and rs2847297 (PTPN2). These putative genetic risk factors were assessed by a stepwise multiple regression analysis adjusted for possible non-genetic risk factors: autoantibody positivity (anti-citrullinated peptide antibody [ACPA] and rheumatoid factor), history of smoking, gender and age at disease onset.

Results

The number of SE alleles (P = 0.002) and risk alleles of peptidyl arginine deiminase type IV gene (PADI4, P = 0.04) had significant impact on progressive joint destruction, as well as following non-genetic factors: ACPA positive (P = 0.0006), female sex (P = 0.006) and younger age of onset (P = 0.02).

Conclusions

In the present study, we found that PADI4 risk allele and HLA-DRB1 shared epitope are independent genetic risks for radiographic progression in Japanese rheumatoid arthritis patients. The results of this study give important knowledge of the risks on progressive joint damage in RA patients.

Goals for rheumatoid arthritis: treating to target or treating to prevent?

Although treat-to-target goals for rheumatoid arthritis (RA) have been well-established through several guidelines in recent years, concerns regarding treat-to-prevent goals for RA remain unclear. RA patients are typically subjected to over- or under-treatment because it is difficult for clinicians to determine the prognosis of RA patients. This typically results in failure to select and identify patient subsets that should receive monotherapy or combination therapy to treat early RA. Understanding treat-to-prevent goals, as well as unfavorable prognoses, risk factors, and prediction methods for RA, is therefore critical for making treatment decisions. Rapid radiographic progression plays a central role in contributing to other composite RA indices, so this may be the best method for defining treat-to-prevent goals for RA. Accordingly, risk factors of rapid radiographic progression have been defined and two prediction models were retrospectively derived based on clinical trial data. Additional studies are required to develop risk models that can be used for accurate predictions.

ACPA-negative RA consists of two genetically distinct subsets based on RF positivity in Japanese

HLA-DRB1, especially the shared epitope (SE), is strongly associated with rheumatoid arthritis (RA). However, recent studies have shown that SE is at most weakly associated with RA without anti-citrullinated peptide/protein antibody (ACPA). We have recently reported that ACPA-negative RA is associated with specific HLA-DRB1 alleles and diplotypes. Here, we attempted to detect genetically different subsets of ACPA-negative RA by classifying ACPA-negative RA patients into two groups based on their positivity for rheumatoid factor (RF). HLA-DRB1 genotyping data for totally 954 ACPA-negative RA patients and 2,008 healthy individuals in two independent sets were used. HLA-DRB1 allele and diplotype frequencies were compared among the ACPA-negative RF-positive RA patients, ACPA-negative RF-negative RA patients, and controls in each set. Combined results were also analyzed. A similar analysis was performed in 685 ACPA-positive RA patients classified according to their RF positivity. As a result, HLA-DRB1*04:05 and *09:01 showed strong associations with ACPA-negative RF-positive RA in the combined analysis (p = 8.8×10⁻⁶ and 0.0011, OR: 1.57 (1.28–1.91) and 1.37 (1.13–1.65), respectively). We also found that HLA-DR14 and the HLA-DR8 homozygote were associated with ACPA-negative RF-negative RA (p = 0.00022 and 0.00013, OR: 1.52 (1.21–1.89) and 3.08 (1.68–5.64), respectively). These association tendencies were found in each set. On the contrary, we could not detect any significant differences between ACPA-positive RA subsets. As a conclusion, ACPA-negative RA includes two genetically distinct subsets according to RF positivity in Japan, which display different associations with HLA-DRB1. ACPA-negative RF-positive RA is strongly associated with HLA-DRB1*04:05 and *09:01. ACPA-negative RF-negative RA is associated with DR14 and the HLA-DR8 homozygote.

HLA-DRβ1*04 typing by simple in-house PCR-SSP technique for rheumatoid arthritis patients

A strong association between rheumatoid arthritis (RA) and human leukocyte antigen (HLA) has been observed in many different populations and that accounts for approximately one-third of the genetic component of RA susceptibility. The greatest effect comes from DRβ1 gene where the strongest association has been found with DRβ1*04 (DR4) allele. As serology has some disadvantages over polymerase chain reaction (PCR)-based techniques and commercially available PCR-based kits are expensive, this study was aimed to standardize simple in-house PCR-SSP technique. Accuracy of this test was further checked with standard PCR-SSOP (RLS) results. The frequency HLA-DRβ1*04 was significantly increased among RA patients when compared with normal controls. In this study, a very simple, convenient and more cost-effective in-house PCR-SSP technique was standardized for HLA-DRβ1*04 typing that is helpful to RA diagnosis in developing countries like India, which can be used as a good screening test.

Associations between six classical HLA loci and rheumatoid arthritis: a comprehensive analysis

Although the HLA region contributes to one-third of the genetic factors affecting rheumatoid arthritis (RA), there are few reports on the association of the disease with any of the HLA loci other than the DRB1. In this study we examined the association between RA and the alleles of the six classical HLA loci including DRB1. Six HLA loci (HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1) of 1659 Japanese subjects (622 cases; 488 anti-cyclic citrullinated peptides (CCP) antibody (Ab) positive (82.6%); 103 anti-CCP Ab negative (17.4%); 31 not known and 1037 controls) were genotyped. Disease types and positivity/negativity for CCP autoantibodies were used to stratify the cases. Statistical and genetic assessments were performed by Fisher's exact tests, odds ratio, trend tests and haplotype estimation. None of the HLA loci were significantly associated with CCP sero-negative cases after Bonferroni correction and we therefore limited further analyses to using only the anti CCP-positive RA cases and both anti-CCP positive and anti-CCP negative controls. Some alleles of the non-DRB1 HLA loci showed significant association with RA, which could be explained by linkage disequilibrium with DRB1 alleles. However, DPB1*02:01, DPB1*04:01 and DPB1*09:01 conferred RA risk/protection independently from DRB1. DPB1*02:01 was significantly associated with the highly erosive disease type. The odds ratio of the four HLA-loci haplotypes with DRB1*04:05 and DQB1*04:01, which were the high-risk HLA alleles in Japanese, varied from 1.01 to 5.58. C*07:04, and B*15:18 showed similar P-values and odds ratios to DRB1*04:01, which was located on the same haplotype. This haplotype analysis showed that the DRB1 gene as well as five other HLA loci is required for a more comprehensive understanding of the genetic association between HLA and RA than analyzing DRB1 alone.

New insights into the functional role of the rheumatoid arthritis shared epitope

The shared epitope (SE) - an HLA-DRB1-encoded 5-amino acid sequence motif carried by the vast majority of rheumatoid arthritis (RA) patients - is a risk factor for severe disease. The mechanistic basis of RA-SE association is unknown. This group has previously demonstrated that the SE acts as a signal transduction ligand that activates nitric oxide and reactive oxygen species production. SE-activated signaling depends on cell surface calreticulin, a known innate immunity receptor previously implicated in immune regulation, autoimmunity and angiogenesis. Recent evidence that the SE enhances the polarization of Th17 cells, which is a key mechanism in autoimmunity, is discussed highlighting one of several potential functional effects of the SE in RA.

Quantifying the economic burden of productivity loss in rheumatoid arthritis

OBJECTIVE

In light of the large number of recent studies and systematic reviews investigating the cost of RA, this article examines the methods used to assess the impact of RA on employment and work productivity, and provides an overview of the issues surrounding work productivity loss in the RA population.

METHODS

A review of the published literature was conducted in order to identify relevant articles. These articles were then reviewed and their methodologies compared. The various methods used to calculate economic loss were then explained and discussed.

RESULTS

We found that although methods of lost productivity and associated costs varied between studies, all suggest that RA is associated with significant burden of illness. Economic analyses that exclude indirect costs will therefore underestimate the full economic impact of RA. However, the methods used to calculate productivity loss have a significant impact on the results of indirect cost analyses, and should be selected carefully when designing such studies. Several factors relating to the disease, the job and socio-demographics have been found to predict work disability.

CONCLUSIONS

Consideration of these factors is vital when measuring the extent of both absenteeism and presenteeism, and will allow for more accurate estimation of the impact of RA on work productivity. This information may also guide interventions aiming to prevent or postpone work disability and job loss.

A role for calreticulin in the pathogenesis of rheumatoid arthritis

Calreticulin (CRT) plays a role in the clearance of dying cells and has been implicated in autoimmunity. Recent evidence indicates that cell surface CRT (csCRT) acts as a signal transducing receptor for the rheumatoid arthritis (RA) shared epitope (SE). The SE binding site on CRT has been mapped to amino acid residues 217-223 in the P-domain. Upon interaction with dendritic cells (DCs), the SE activates potent immune regulatory events. In CD8α(+) DCs, which express higher abundance of csCRT, the SE inhibits the tolerogenic enzyme indoleamine 2,3 dioxygenase with resultant inhibition of regulatory T (Treg) cell differentiation. In CD8α(-) DCs, the SE ligand increases secretion of IL-6 and IL-23 and facilitates generation of Th17 cells, a T cell subset known to play a role in autoimmunity. On the basis of these recent findings, we discuss the possibility that the csCRT may play a pathogenic role in RA by transducing SE-activated Th17-polarizing signals.

Prognostic Factors of Radiological Damage in Rheumatoid Arthritis: A 10-year Retrospective Study

Objective.

To describe the longterm clinical and radiological outcomes in rheumatoid arthritis (RA) in a cohort in northwestern Greece; and to investigate predictive factors of radiological damage at the 10-year followup in patients with RA.

Methods.

We studied the disease course and outcome of 144 patients with RA and radiographs of the hands and wrists available at baseline and at 10 years. Baseline measurements and time-averaged measures of swollen joint count (SJC) and inflammatory markers [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)] were tested in univariate analysis, and then those presenting a statistically significant association with either Larsen score at 10 years or annual progression rate were included in 2 logistic regression models in order to determine relevant independent prognostic factors.

Results.

A significant clinical improvement was noted, associated with a decrease of inflammatory markers along the timepoints. Larsen score and the number of erosive joints were increased. In the univariate analysis, both final Larsen score at 10 years and accelerated annual radiological progression rate were significantly associated with baseline radiographic measurements (Larsen score and number of erosive joints), the presence of autoantibodies [anticyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factor of IgA and IgM isotype], disease duration, and time-averaged measures of ESR, CRP, and SJC. In the logistic regression analysis, the baseline Larsen score, anti-CCP antibodies, and time-averaged CRP presented significant and independent associations with Larsen score at 10 years. An accelerated annual radiological progression rate was also predicted by baseline Larsen score and time-averaged measures of SJC and CRP.

Conclusion.

Despite clinical improvement, the radiologic progression of RA continues over time, because of the underlying inflammatory process. Baseline radiographic damage, anti-CCP antibodies, and time-averaged CRP constitute the main predictive factors of poor radiologic outcome in the long term.

Clinical application and evaluation of anti-TNF-alpha agents for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease that dramatically impairs quality of life. A number of compounds are available to treat RA, but they vary in effectiveness. Thus, no optimal treatment strategy has been defined. Currently, disease-modifying anti-rheumatic drugs (DMARDs) and anti-tumor necrosis factor-alpha (anti-TNF-alpha) agents are considered the treatments of choice. For patients with inadequate responses to DMARD therapy, one recommended therapeutic alternative is anti-TNF-alpha therapy. Anti-TNF-alpha agents are effective and have rapid onset of action compared with DMARDs. Elucidating the differences in effectiveness of anti-TNF-alpha compounds has important clinical implications. By comparing the efficacy, safety and use principle of different treatment options, this review focuses on providing important information about three anti-TNF-alpha compounds (etanercept, infliximab, and adalimumab) to help define optimal treatments for RA patients.

The impact of HLA-DRB alleles on the subclass titres of antibodies against citrullinated peptides

OBJECTIVES

The association between HLA-DR haplotypes and RA have been well established. However, the molecular mechanisms of how HLA mediates susceptibility and/or progression of the disease remain elusive. We therefore turned to the RA-specific antibodies directed against citrullinated peptide antigens (ACPAs) and investigated the association between HLA-DRB1 shared epitope (SE) alleles and the IgG subclass titres of cyclic citrullinated peptide (CCP)- and mutated citrullinated vimentin (MCV)-specific antibodies.

METHODS

One hundred and twenty-seven RA patients were typed for their HLA-DRB1 haplotypes applying low resolution and alleles potentially carrying the SE were sequenced. All patients' sera were analysed by ELISA for the presence of ACPA and 77 patients positive for CCP-specific antibodies were further analysed for the respective IgG subclasses. Subclass titres were then correlated to the presence of a SE. Finally, all patients were screened for the HLA-DRB4-associated splice variant.

RESULTS

We found a gene dosage effect of the HLA-DRB1*04-associated SE on both the MCV- and CCP-specific IgG3 levels. The HLA-DRB4-associated splice variant accumulates in ACPA-negative RA patients.

CONCLUSIONS

Both the dose-dependent increase in IgG3 among ACPA and the accumulation of the splice variant in ACPA-negative patients imply differential expression of the HLA alleles as the mechanism contributing to the susceptibility and/or disease progression of RA. The preponderance of IgG3 hints at a skewing towards a Th1 response and is reminiscent of increased signal strengths at the immunological synapse. Likewise, the abrogation of HLA-DRB4 expression due to the splice variant reduces the signal strength and seems to protect from ACPA development.

Protection against anti-citrullinated protein antibody-positive rheumatoid arthritis is predominantly associated with HLA-DRB1*1301: a meta-analysis of HLA-DRB1 associations with anti-citrullinated protein antibody-positive and anti-citrullinated protein antibody-negative rheumatoid arthritis in four European populations

OBJECTIVE

The protective effect of HLA-DRB1 alleles on the development of rheumatoid arthritis (RA) is poorly understood. The aim of this study was to perform a meta-analysis of 4 European populations to investigate which HLA-DRB1 alleles are associated with protection in anti-citrullinated protein antibody (ACPA)-positive RA and ACPA-negative RA.

METHODS

Data for >2,800 patients and >3,000 control subjects for whom information on HLA-DRB1 typing and ACPA status was available were collected from 4 European countries: Norway, Sweden, The Netherlands, and Spain. The odds ratios (ORs) and 95% confidence intervals (95% CIs) associated with the different HLA-DRB1 alleles were analyzed in a combined meta-analysis focused on protective alleles and classifications. The analysis of ACPA-positive RA was stratified for the shared epitope (SE) alleles, to correct for skewing due to this association.

RESULTS

In ACPA-positive RA, the only alleles that conveyed protection after stratification for SE were HLA-DRB1*13 alleles (OR 0.54 [95% CI 0.38-0.77]). The protective effect of the allele classifications based on the DERAA and D70 sequences was no longer present after exclusion of DRB1*13 (for D70, OR 0.97 [95% CI 0.75-1.25]), indicating that DRB1*13, rather than the DERAA or D70 sequence as such, is associated with protection. Among the DRB1*13 alleles, only DRB1*1301 was associated with protection (OR 0.24 [95% CI 0.09-0.59]). Protection appeared to follow a north-to-south gradient, with the strongest association in northern European countries. In ACPA-negative RA, there were no robust associations with HLA-DRB1 alleles.

CONCLUSION

Our data do not support any of the classifications of protective alleles and indicate that protection against ACPA-positive RA is predominantly associated with HLA-DRB1*1301.