Shared epitopes and rheumatoid arthritis: disease associations in Greece and meta-analysis of Mediterranean European populations

Shared epitope and polymorphism of MICA and NKG2D encoding genes in Greek and Polish patients with rheumatoid arthritis

The present study aimed to analyse and compare the distribution of MICA (rs1051792) and NKG2D/KLRK1 (rs1154831, rs1049174, rs2255336) polymorphisms in 61 Greek and 100 Polish patients with rheumatoid arthritis in relation to the presence of the HLA-DRB1 shared epitope and clinical parameters. Genotyping of selected polymorphism was performed using real-time PCR. HLA-DRB1 shared epitope alleles segregated differently in Greek and Polish patients but in both populations were detected in over 60% of cases. The rs1051792-A variant was more common among SE-positive Polish patients (p = 0.003) while the rs1049174-G allele was more frequently observed in Greeks than in Poles (p < 0.001). Moreover, among Greek patients, the rs1051792-GG homozygotes more frequently presented with anti-CCP antibodies and rheumatoid factor (RF), while carriers of the rs1049174-G variant and rs1154831-CC homozygotes were characterized by lower disease activity scores (p < 0.05 in all cases). These results imply that, in addition to the HLA-DRB1 SE alleles, MICA and NKG2D polymorphisms may also play a role in rheumatoid arthritis.

Overlapping Sjogren's syndrome reduces the probability of reaching target in rheumatoid arthritis patients: a propensity score matched real-world cohort from 2009 to 2019

Background

Overlapping Sjogren’s syndrome (SS) is not uncommon in rheumatoid arthritis (RA) and considered as a probable detrimental factor of RA. But data on the impact of overlapping SS on RA therapeutic response is limited. Our current study aimed to identify the effect in a real-world cohort from 2009 to 2019.

Methods

The medical records of RA patients who visited the rheumatology clinic of our medical center from 2009 to 2019 were reviewed. Their composite disease activity scores at each follow-up point were collected. The therapeutic response between RA patients with SS (RA-SS) and without (RA-noSS) was compared. To correct confounders which may affect the therapeutic response, both propensity score matched and unmatched cohorts were analyzed by using the Cox proportional hazards model.

Results

Among the 1099 RA patients, 129 (11.7%) overlapped with SS were validated by positive anti-SSA or a minor salivary gland biopsy with histological changes suggestive of SS. After propensity score matching based on their baseline characteristics, 126 of 129 RA-SS and 126 of 970 RA-noSS patients were statistically extracted. Overlapping SS was associated with a 29%, 26%, 18%, and 22% lower probability of reaching remission defined by DAS28-ESR, DAS28-CRP, SDAI, and CDAI in RA patients, respectively. Similar decreased probability of reaching low disease activity was also observed. Although ESR was most significantly affected (HR 0.69, 95% CI 0.61–0.79), other component of composite RA disease activity score was also affected by overlapping SS. Stratification by age, RF/ACPA status, or baseline DAS28-CRP was not associated with change of results.

Conclusions

Overlapping SS is associated with lower probability of reaching remission or low disease activity in RA patients and should be regarded as one of the poor prognostic factors.

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.

The epidemiology of Sjögren's syndrome

Sjögren's syndrome is a chronic systemic autoimmune disease characterized by lymphocytic infiltration of exocrine glands. It can present as an entity by itself, primary Sjögren's syndrome (pSS), or in addition to another autoimmune disease, secondary Sjögren's syndrome (sSS). pSS has a strong female propensity and is more prevalent in Caucasian women, with the mean age of onset usually in the 4th to 5th decade. Clinical presentation varies from mild symptoms, such as classic sicca symptoms of dry eyes and dry mouth, keratoconjunctivitis sicca, and xerostomia, to severe systemic symptoms, involving multiple organ systems. Furthermore, a range of autoantibodies can be present in Sjögren's syndrome (anti-SSA/Ro and anti-SSB/La antibodies, rheumatoid factor, cryoglobulins, antinuclear antibodies), complicating the presentation. The heterogeneity of signs and symptoms has led to the development of multiple classification criteria. However, there is no accepted universal classification criterion for the diagnosis of Sjögren's syndrome. There are a limited number of studies that have been published on the epidemiology of Sjögren's syndrome, and the incidence and prevalence of the disease varies according to the classification criteria used. The data is further confounded by selection bias and misclassification bias, making it difficult for interpretation. The aim of this review is to understand the reported incidence and prevalence on pSS and sSS, the frequency of autoantibodies, and the risk of malignancy, which has been associated with pSS, taking into account the different classification criteria used.

A systems genetics approach provides a bridge from discovered genetic variants to biological pathways in rheumatoid arthritis

Genome-wide association studies (GWAS) have yielded novel genetic loci underlying common diseases. We propose a systems genetics approach to utilize these discoveries for better understanding of the genetic architecture of rheumatoid arthritis (RA). Current evidence of genetic associations with RA was sought through PubMed and the NHGRI GWAS catalog. The associations of 15 single nucleotide polymorphisms and HLA-DRB1 alleles were confirmed in 1,287 cases and 1,500 controls of Japanese subjects. Among these, HLA-DRB1 alleles and eight SNPs showed significant associations and all but one of the variants had the same direction of effect as identified in the previous studies, indicating that the genetic risk factors underlying RA are shared across populations. By receiver operating characteristic curve analysis, the area under the curve (AUC) for the genetic risk score based on the selected variants was 68.4%. For seropositive RA patients only, the AUC improved to 70.9%, indicating good but suboptimal predictive ability. A simulation study shows that more than 200 additional loci with similar effect size as recent GWAS findings or 20 rare variants with intermediate effects are needed to achieve AUC = 80.0%. We performed the random walk with restart (RWR) algorithm to prioritize genes for future mapping studies. The performance of the algorithm was confirmed by leave-one-out cross-validation. The RWR algorithm pointed to ZAP70 in the first rank, in which mutation causes RA-like autoimmune arthritis in mice. By applying the hierarchical clustering method to a subnetwork comprising RA-associated genes and top-ranked genes by the RWR, we found three functional modules relevant to RA etiology: "leukocyte activation and differentiation", "pattern-recognition receptor signaling pathway", and "chemokines and their receptors".These results suggest that the systems genetics approach is useful to find directions of future mapping strategies to illuminate biological pathways.

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.

Association of IL4R single-nucleotide polymorphisms with rheumatoid nodules in African Americans with rheumatoid arthritis

INTRODUCTION

To determine whether IL4R single-nucleotide polymorphisms (SNPs) rs1805010 (I50V) and rs1801275 (Q551R), which have been associated with disease severity in rheumatoid arthritis (RA) patients of European ancestry, relate to the presence of rheumatoid nodules and radiographic erosions in African Americans.

METHODS

Two IL4R SNPs, rs1805010 and rs1801275, were genotyped in 749 patients from the Consortium for Longitudinal Evaluation of African-Americans with Early Rheumatoid Arthritis (CLEAR) registries. End points were rheumatoid nodules defined as present either by physical examination or by chest radiography and radiographic erosions (radiographs of hands/wrists and feet were scored using the modified Sharp/van der Heijde system). Statistical analyses were performed by using logistic regression modeling adjusted for confounding factors.

RESULTS

Of the 749 patients with RA, 156 (20.8%) had rheumatoid nodules, with a mean age of 47.0 years, 84.6% female gender, and median disease duration of 1.9 years. Of the 461 patients with available radiographic data, 185 (40.1%) had erosions (score>0); their mean age was 46.7 years; 83.3% were women; and median disease duration was 1.5 years. Patients positive for HLA-DRB1 shared epitope (SE) and autoantibodies (rheumatoid factor (RF) or anti-cyclic citrullinated peptide (CCP)) had a higher risk of developing rheumatoid nodules in the presence of the AA and AG alleles of rs1801275 (odds ratio (OR)adj=8.08 (95% confidence interval (CI): 1.60-40.89), P=0.01 and ORadj=2.97 (95% CI, 1.08 to 8.17), P=0.04, respectively). Likewise, patients positive for the HLA-DRB1 SE and RF alone had a higher risk of developing rheumatoid nodules in presence of the AA and AG alleles of rs1801275 (ORadj=8.45 (95% CI, 1.57 to 45.44), P=0.01, and ORadj=3.57 (95% CI, 1.18 to 10.76), P=0.02, respectively) and in the presence of AA allele of rs1805010 (ORadj=4.52 (95% CI, 1.20 to 17.03), P=0.03). No significant association was found between IL4R and radiographic erosions or disease susceptibility, although our statistical power was limited by relatively small numbers of cases and controls.

CONCLUSIONS

We found that IL4R SNPs, rs1801275 and rs1805010, are associated with rheumatoid nodules in autoantibody-positive African-American RA patients with at least one HLA-DRB1 allele encoding the SE. These findings highlight the need for analysis of genetic factors associated with clinical RA phenotypes in different racial/ethnic populations.

Relationship Between Cyclic Citrullinated Peptide Antibodies Positivity and HLA-DRB1 Shared Epitope Alleles in Patients with Rheumatoid Arthritis in Turkey

Objective: The most characteristic genetic risk factors for rheumatoid arthritis (RA), the HLA-DRB1 shared epitope (SE) alleles, encode for a common amino acid sequence in the peptide-presenting part of the HLA class II molecule. These SE alleles have been described recently to be a risk factor for the development of antibodies against citrullinated proteins in RA. The current study was performed to investigate the association between the cyclic citrullinated peptide antibodies (anti-CCP) and HLA-DR1 HLA-DRB1 shared epitope alleles in patients with RA in Turkey.

Materials and Methods: Sixty patients with RA who were newly diagnosed or under conventional treatment in our clinic and 60 healthy volunteers as controls were enrolled in the study. In patients with RA anti-CCP levels were investigated with enzyme-linked immunosorbent assay and HLA-DRB1 subtyping and SE was assessed by polymerase chain reaction. Only anti-CCP was measured in healthy volunteers.

Results: SE was positive in 50% of the patients with RA. Amongst the SE carriers, 30% of them were carrying double copy of SE. While anti-CCP was positive in 73,3% of patients with RA, this ratio was 0% in healthy volunteers. We determined that the existence of SE increases the positivity of anti-CCP (OR=4,3, 95% [CI], P=0.04 ), and a significant relationship was found between the anti-CCP positivity and the RF positivity. (OR=5,3, 95% [CI] P<0.05).

Conclusion: The results of the present study revealed that Turkish patients with RA carrying SE with HLA-DRB1 genes is significantly related with the production of anti-CCP. The diagnostic sensitivity and specificity of anti-CCP for RA is determined as 73,3% and 100% respectively. (Turk J Rheumatol 2010; 25: 12-8)

New classification of HLA-DRB1 alleles in rheumatoid arthritis susceptibility: a combined analysis of worldwide samples

Introduction

Rheumatoid arthritis (RA) is a complex polygenic disease of unknown etiology. HLA-DRB1 alleles encoding the shared epitope (SE) (RAA amino acid pattern in positions 72 to 74 of the third hypervariable region of the DRβ1 chain) are associated with RA susceptibility. A new classification of HLA-DRB1 SE alleles has been developed by Tezenas du Montcel and colleagues to refine the association between HLA-DRB1 and RA. In the present study, we used RA samples collected worldwide to investigate the relevance of this new HLA-DRB1 classification in terms of RA susceptibility across various Caucasoid and non-Caucasoid patients.

Methods

Eighteen subsamples were defined from a total number of 759 cases and 789 controls and grouped in 10 samples on the basis of their ethnic origin. HLA-DRB1 alleles were divided into five groups (S₁, S₂, S_3D, S_3P, and X) according to the new HLA-DRB1 allele classification. The whole analysis was performed by comparing carrier frequencies for the five HLA-DRB1 allele groups between RA patients and controls across the 10 Caucasoid and non-Caucasoid samples. The Mantel-Haenszel method of meta-analysis provided a global odds ratio (OR) estimate with 95% confidence interval (CI).

Results

A positive association with RA susceptibility was found for S₂ allele carriers (OR 2.15, 95% CI 1.54 to 3.00; p < 10^-5) and S_3P allele carriers (OR 2.74, 95% CI 2.01 to 3.74; p < 10^-5). A negative association was found for S₁ alleles (OR 0.60, 95% CI 0.48 to 0.76; p < 10^-4) and X alleles (OR 0.58, 95% CI 0.39 to 0.84; p = 4 × 10^-3). No significant association was highlighted for the S_3D group of alleles (OR 0.89, 95% CI 0.69 to 1.14; p = 0.89). The complementary genotype analysis fit with the genotype risk hierarchy previously reported in Caucasoid RA patients.

Conclusion

So far, the present study is the first attempt to investigate the relevance of this new HLA-DRB1 classification in terms of RA susceptibility on both Caucasoid and non-Caucasoid samples. Our results support the hypothesis of a differential role played by different HLA-DRB1 allele groups in RA susceptibility across different ethnic backgrounds and confirm the interest of such an HLA-DRB1 classification in differentiating predisposing and protective alleles.

The association of HLA-DRB1 alleles with rheumatoid arthritis in the Chinese Shantou population: a follow-up study

We investigated the distribution of HLA-DRB1 alleles in a sample of the Chinese Shantou population, and explored the relationship between HLA-DRB1 alleles and the susceptibility and clinical features of rheumatoid arthritis (RA). We studied 117 consecutive patients with RA and control groups, including 38 cases of systemic lupus erythematosus and 100 healthy individuals. HLA-DRB1 genotyping was performed using PCR with sequence-specific primers. HLA-DRB1*04 subtypes were detected using spot hybridization of PCR products with sequence-specific oligonucleotide probes. We compared the frequency of HLA-DRB1 alleles in healthy control patients with that in patients with RA. Patients with RA were evaluated for sex, age at disease onset, disease duration, extra-articular involvement, presence of autoantibodies, global functional status, and radiographic damage. The frequency of HLA-DRB1*04 was found to be significantly higher in RA patients than in healthy individuals (49.6% vs 18.0%, odds ratio = 4.478, P < 0.001). HLA-DRB1*0405 was the most prominently associated subtype in RA patients (62.1% vs 27.8%, odds ratio = 4.255, P = 0.011). Compared with the HLA-DRB1*04-negative RA group, the mean duration of RA in the HLA-DRB1*04-positive RA group was longer, and the mean age at disease onset was lower. A 2-9 year follow-up study was performed, and the risk factors associated with the radiographic progression of RA were determined. Logistic regression analysis revealed that only HLA-DRB1*04 alleles were significantly associated with the radiographic progression of RA (B = 2.652, P = 0.018, Exp(B) = 14.182). Our observations indicated that the HLA-DRB1*04 alleles, especially the subtype HLA-DRB1*0405, were significantly associated with RA susceptibility in the Chinese Shantou population. The HLA-DRB1*04 alleles may be associated with the severity of RA.

Incidence and Prevalence of Rheumatoid Arthritis, Based on the 1987 American College of Rheumatology Criteria: A Systematic Review

OBJECTIVES

To conduct a systematic review of incidence and prevalence studies of rheumatoid arthritis (RA), based on the 1987 revised American College of Rheumatology (ACR) criteria, to compare their methodologies and summarize their results, and to investigate the possible geographic variations and changes over time in the frequency of the disease.

METHODS

We conducted a Medline search between January 1988 and December 2005. Studies reporting the incidence and prevalence of RA in adult populations (16 to 20 years and over), based on 1987 ACR criteria, were eligible for inclusion. From each study included, we extracted the country, year of publication, type of study (retrospective, prospective, or cross-sectional), and incidence or prevalence rates. The study areas were grouped into (a) North American countries; (b) north European countries; (c) south European countries; and (d) developing countries. We examined the geographical differences of prevalence and incidence rates using the Mann-Whitney and the Kruskall-Wallis tests.

RESULTS

A total of 28 studies were identified meeting the inclusion criteria. Nine were incidence studies, 17 were prevalence studies, and 2 estimated both prevalence and incidence rates. Incidence studies were not available from developing countries. There is a significant difference of prevalence estimates between northern European and American countries and developing countries. South European countries have lower median incidence rates than North American and north European countries. As concerning the time trends of RA occurrence, only 3 incidence studies provided secular data from the same study area, based on ACR criteria, using the same methods of case ascertainment. Two of these studies indicate a decreasing incidence of RA in Finland and United States of America.

CONCLUSIONS

The occurrence of RA varies among countries and areas of the world. A decreasing trend has been observed in countries characterized by high rates of RA incidence and prevalence. However, the relatively small number of studies for most areas of the world and the lack of incidence studies for the developing countries limits the understanding of worldwide RA epidemiology.

Association of rheumatoid factor production with FcgammaRIIIa polymorphism in Taiwanese rheumatoid arthritis

Fcgamma receptors (FcgammaR) impact upon the development of inflammatory arthritis through immune complex stimulation and proinflammatory cytokine production. FcgammaRIIa, FcgammaRIotaIotaIotaa and FcRgammaIIIb polymorphisms were genotyped in 212 rheumatoid arthritis (RA) patients and 371 healthy control subjects using an allelic-specific polymerase chain reaction (PCR). No significant skewing in the distribution of FcgammaRIIa H/R131, FcgammaRIIIa F/V158 and FcgammaRIIIb NA1/NA2 was found between RA patients and healthy control subjects. However, a significant skewing distribution of the FcgammaRIIIa F/V158 polymorphism was observed between rheumatoid factor (RF)-positive versus RF-negative RA patients (P = 0.01). The low-affinity FcgammaRIIIa F158 allele seems to have a protective role in RF production, in comparison with the FcgammaRIIIa V158 allele (P = 0.004; OR = 0.485; 95% CI: 0.293-0.803). A high frequency of FcgammaRIIIa F/F158 was identified in RA patients with negative RF compared with RF-positive patients (for FF158 versus FV158 + VV158; P = 0.002; OR = 0.372; 95% CI: 0.194-0.713). In addition, no association was found between FcgammaRIIa H/R131, FcgammaRhoIIIa F/V158 and FcgammaRIIIb NA1/NA2 polymorphisms and other clinical parameters. The results of this study suggest that three activating FcgammaRs polymorphisms lack association with RA but FcgammaIIIa F/V158 polymorphism may influence RF production and IgG RF immune complex handling in Taiwanese RA patients.

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

OBJECTIVE

The strongest known genetic association in rheumatoid arthritis (RA) is with HLA-DRB1 alleles that share a similar amino acid sequence, termed the shared epitope (SE). Although many studies have examined the association of the SE with disease severity, the results have been inconsistent, which may reflect the relatively small sample sizes or ethnic differences. The aim of this study was to assess the association of HLA-DRB1 SE alleles and genotype with the development of bony erosions in RA by meta-analysis.

METHODS

We identified English-language articles published between January 1, 1987 and June 1, 1999 through Medline, EMBase, and manual searches of 6 relevant journals. Included were studies in which molecular typing of HLA-DRB1 alleles was performed and in which the presence or absence of bony erosions was reported. Data were extracted from the studies, and erosions were coded as present or absent. Authors were contacted for missing information and data on individual patients.

RESULTS

A total of 29 studies and 3,240 patients were available for analysis. The summary odds ratios (ORs), when all patients were evaluated as a single group, demonstrated a significant association of the presence of the SE (2 or 1 versus 0 SE alleles) with erosions (OR 2.0; 95% confidence interval [95% CI] 1.8-2.2), although significant heterogeneity was present (P = 0.002). Subgroup analyses demonstrated the important influence of ethnic background. For example, no association of the SE with erosions was demonstrated in Greeks (OR 0.8 [95% CI 0.2-1.5]). In contrast, there was a striking dose-dependent relationship in southern European Caucasians and Asians, with ORs as high as 6.2 and 5.4, respectively, in patients with 2 SE alleles. Although our ability to assess the relationship between SE genotype and erosions was limited, particular importance of the DRB1*0401 SE allele was suggested in an analysis restricted to northern European Caucasians.

CONCLUSION

The SE is associated with the development of erosive disease in many ethnic groups; however, striking exceptions exist. These variations may be due to allele differences between populations, such as the frequency of DRB1*0401 among different ethnic groups. Further study to better understand the genetic and environmental differences between these populations may provide insight into mechanisms that influence the clinical expression of RA.

Lack of association of the HLA-DRB1 shared epitope with rheumatoid nodules: An individual patient data meta-analysis of 3,272 Caucasian patients with rheumatoid arthritis

OBJECTIVE

The objective of this individual patient data (IPD) meta-analysis was to examine the relationship of rheumatoid nodules to the HLA-DRB1 shared epitope (SE) and to individual SE genotypes.

METHODS

English-language studies that enrolled adult non-Hispanic Caucasian patients with rheumatoid arthritis (RA) were identified by searches of Medline and Embase, and by manual searches of medical journals. All authors were contacted for IPD. Meta-analysis was performed to assess the association of SE presence, dose, and genotype with rheumatoid nodules. Meta-analyses adjusted for disease duration and cumulative meta-analyses were also performed to assess the influence of RA duration and year of study publication on the results.

RESULTS

A total of 24 studies and 3,272 patients were available for analysis. IPD were obtained for 22 of the studies. There was a nonsignificant association between the presence of the SE (i.e., 1 or 2 alleles versus 0 alleles) and rheumatoid nodules (summary odds ratio [OR] 1.3, 95% confidence interval [95% CI] 0.97-1.6). Analysis by SE genotype, however, demonstrated a weak relationship with inheritance of a single DRB1*0401 SE allele (OR 1.4, 95% CI 1.1-1.8). No other genotypes achieved statistical significance in the adjusted or unadjusted analyses.

CONCLUSION

The presence of the HLA-DRB1 SE does not appear to significantly increase the risk of rheumatoid nodules among Caucasian patients with RA. Analysis by DRB1 SE genotype was uninformative, suggesting only a potential (and at most modest) role of the DRB1*0401 SE allele. Results from this IPD meta-analysis implicate other genetic, stochastic, and/or environmental factors in the susceptibility to rheumatoid nodules.

Genotypes and phenotypes: should genetic markers and clinical predictors drive initial treatment decisions in rheumatic diseases?

Using patients' genetic and phenotypic profiles to identify the best available drug therapy for individual cases remains a clinical aspiration. Considerable recent research has developed this theme in rheumatoid arthritis (RA). Seven reports have evaluated how the high-risk epitope and other genes influence RA susceptibility and severity. There is strong evidence that the shared epitope influences susceptibility, but inconclusive evidence concerning whether it effects severity. The interleukin-1 gene cluster and IL-4/IL-4 genes influence erosive disease, but their effects are mainly in late RA. A further ten studies examined links with erosive disease. Fewer reports evaluated phenotypes: six studies examined outcome predictions using rheumatoid factor and antikeratin/anticyclic citrullinated peptide antibodies and two looked at conventional clinical measures. Anticyclic citrullinated peptide antibodies are useful in establishing the diagnosis of RA, but rheumatoid factor potentially provides the most useful prognostic information. The value of genotyping RA patients in defining their clinical course and determining the most suitable treatment remains unproven.

Influence of human leukocyte antigen-DRB1 on the susceptibility and severity of rheumatoid arthritis

BACKGROUND AND OBJECTIVES

All human leukocyte antigen (HLA)-DRB1 alleles associated with rheumatoid arthritis (RA) encode a conserved amino acid sequence (QKRAA, QRRAA, or RRRAA) at position 70-74 in the third hypervariable region (HVR3) of the DRbeta(1) chain, which is commonly called the shared epitope (SE). Several studies, however, have associated the HLA-DRB1 gene in RA severity and progression rather than with susceptibility. Moreover, the association with disease severity and presence of the SE varies among different ethnic populations. HLA-DRB1 alleles also influence the disease onset. In this manuscript, the role of the HLA genes in RA was examined.

METHODS

A retrospective review of the literature was conducted to analyze the influence of the HLA-class II genes on the susceptibility, severity and protection against RA.

RESULTS

The HLA-DRB1*0401/*0404 genotype was associated with a higher risk for early disease onset in more severe forms in patients from the United Kingdom (UK). In northwest Spain, RA onset under 40 years is strongly associated with HLA-DRB1*0401 and *0404. In contrast, RA onset above 60 years is associated with HLA-DRB1*01. The protection against RA linked to some HLA-DRB1 alleles encoding a DERAA sequence of amino acids at position 70-74 in the HVR3 of the DRbeta1 chain, and specifically aspartic acid (D) at position 70 of this chain, recently was confirmed in both UK and northwest Spanish populations. Besides HLA-class II, other genes may be implicated in RA. Polymorphism in the tumor necrosis factor (TNF) region seems to be associated with RA, even in patients without the HLA-DRB1 SE. However, other genes such as interleukin-1 (IL-1) and corticotropin-releasing hormone may play a role in susceptibility to RA.

CONCLUSIONS

The additive effect of various genes may account for the development of RA and its clinical severity.

Extraarticular manifestations of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory disease that can involve other tissues and organs as well as synovial joints. This chapter reviews the clinical aspects of extra-articular RA, from the early descriptions in rheumatology texts to reports from more recent cross-sectional and inception cohort studies. There is no agreed classification for these manifestations and, because criteria and definitions vary so much, this report includes not only the classic extra-articular features but also the non-articular complications of RA, for example normochromic normocytic anaemia and chronic leg ulcers, and the important disease-associated comorbidities, including non-Hodgkin's lymphoma, ischaemic heart disease and osteoporosis. Incidence and frequency figures for extra-articular RA vary according to study design. Nodules are the most common extra-articular feature, and are present in up to 30%; many of the other classic features occur in 1% or less in normal clinic settings. Sjögren's syndrome, anaemia of chronic disease and pulmonary manifestations are relatively common - in 6-10% - are frequently present in early disease and are all related to worse outcomes measures of rheumatoid disease, in particular functional impairment and mortality. Currently, there are no reliable predictors for these features in early RA, although they are associated with men, smokers, more severe joint disease, worse function, high levels of inflammatory markers, and the presence of rheumatoid factor (RF), antinuclear antibodies (ANA) and the RA HLA-related shared epitope. Many of these manifestations are related to the more active and severe RA, so early and more aggressive RA drug therapies are being employed and, although evidence from randomised studies is not available, this approach would seem appropriate in view of the adverse effect of extra-articular manifestations on RA outcomes. Unfortunately, specific therapies for extra-articular manifestations of RA are largely disappointing or unavailable, except for steroids and cyclophosphamide for vasculitis. The place for biological therapies is still not clear. Pulmonary fibrosis in RA has a poor prognosis whether treated with large doses of steroids, cytotoxic or disease modifying drugs like cyclosporine, or biologics. In summary, extra-articular features and non-articular complications of RA are common and are generally related to worse disease. They need to be recognised early and managed promptly.