Independent association of rheumatoid factor and the HLA-DRB1 shared epitope with radiographic outcome in rheumatoid arthritis

Clinical Implications of Shared Epitope and Anti-citrullinated Peptide Antibody in Patients With Rheumatoid Arthritis

Objective

The shared epitope (SE) and anti-citrullinated peptide antibody (ACPA) are involved in the pathogenesis of rheumatoid arthritis (RA). This study evaluated the clinical implications of SE and ACPA in terms of disease manifestation and response to biologic disease modifying anti-rheumatic drugs (DMARDs).

Methods

Patients with identified human leukocyte antigen (HLA)-DRB1 alleles were included to compare the clinical characteristics and drug survival rate of tumor necrosis factor (TNF) inhibitors or abatacept based on the presence of SE and ACPA.

Results

Of the 533 patients with identified HLA-DRB1 alleles, 329 patients (61.7%) with SE alleles showed higher disease activity and erosive changes compared to patients without SE alleles. SE-positive patients were more likely to start biologic (b-) or targeted synthetic DMARDs (tsDMARDs) within the first 5 years (p=0.020). The presence of SE, smoking, dyslipidemia, and higher erythrocyte sedimentation rate were independently associated with the initiation of b- or tsDMARDs (p=0.016, 0.028, 0.031, and 0.001, respectively). The presence of SE and ACPA did not affect the drug survival rate of TNF inhibitors, whereas the abatacept retention rate was higher in ACPA-positive patients (p=0.024).

Conclusion

The presence of SE affected disease characteristics and prognosis in Korean patients with RA without a significant impact on drug survival rate of TNF inhibitors and abatacept. ACPA positivity was associated with abatacept drug retention, suggesting that abatacept may be helpful in ACPA-positive patients than in ACPA-negative patients.

Trajectory clusters of radiographic progression in patients with rheumatoid arthritis: associations with clinical variables

OBJECTIVES

Identification of trajectories of radiographic damage in rheumatoid arthritis (RA) by clustering patients according to the shape of their curve of Sharp-van der Heijde scores (SHSs) over time. Developing models to predict their progression cluster from baseline characteristics.

METHODS

Patient-level data over a 2-year period from five large randomised controlled trials on tumour necrosis factor inhibitors in RA were used. SHSs were clustered in a shape-respecting manner to identify distinct clusters of radiographic progression. Characteristics of patients within different progression clusters were compared at baseline and over time. Logistic regression models were developed to predict trajectory of radiographic progression using information at baseline.

RESULTS

In total, 1887 patients with 7738 X-rays were used for cluster analyses. We identified four distinct clusters with characteristic shapes of radiographic progression: one with a stable SHS over the whole 2-year period (C0/lowChange; 86%); one with relentless progression (C1/rise; 5.8%); one with decreasing SHS (C2/improvement; 6.9%); one going up and down (C3/bothWays; 1.4%) of the SHS. Robustness of clusters were confirmed using different clustering methods. Regression models identified disease duration, baseline C-reactive protein (CRP) and SHS and treatment status as predictors for cluster assignment.

CONCLUSIONS

We were able to identify and partly characterise four different clusters of radiographic progression over time in patients with RA, most remarkably one with relentless progression and another one with amelioration of joint damage over time, suggesting the existence of distinct patterns of joint damage accrual in RA.

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

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

Outcome of patients with early arthritis without rheumatoid factor and ACPA and predictors of rheumatoid arthritis in the ESPOIR cohort

OBJECTIVE

To describe the disease course of patients with early arthritis without rheumatoid factor (RF) and anti-citrullinated protein auto-antibodies (ACPA) in an inception cohort. To determine baseline predictors of fulfilling 2010 ACR/EULAR criteria for rheumatoid arthritis (RA) for these patients within 3 years.

METHOD

Patients included in the multicenter ESPOIR cohort were compared at baseline and 3 years by whether they were negative for RF and ACPA ("seronegative") or positive for RF and/or ACPA ("seropositive"). Univariate analysis was used to determine the association between baseline variables in seronegative patients and RA classification. Stepwise multiple logistic regression was used to identify predictors of RA classification within 3 years, estimating odds ratios (ORs).

RESULTS

Among 354 seronegative patients, 224/340 with available data (65.9%) fulfilled RA classification at baseline and 189/233 (81.1%) at 3 years. As compared with seropositive patients, seronegative patients had lower DAS28 (p = 0.002) and lower modified total Sharp score (mTSS; p = 0.026) at baseline; DAS28 remission was similar (p = 0.634), but radiographic progression rate was lower in seronegative patients (p <  0.001) at 3 years. In seronegative patients, factors predicting RA classification within 3 years were additive (OR = 3.61), bilateral (OR = 2.59) and hand, wrist or forefeet involvement (OR = 3.87); presence of a trigger event (OR = 3.57); pain at rest (OR = 2.76); morning stiffness (OR = 2.62); number of tender joints (OR = 23.73); and mTSS (OR = 2.56).

CONCLUSION

"Seronegative" patients have less active disease at baseline and less radiographic progression during follow-up than "seropositive" patients. With inflammatory pain, symmetric involvement of numerous small joints and erosive disease, a classification of RA is likely.

Human Leukocyte Antigen-Disease Associations in Rheumatoid Arthritis

The cause and pathogenesis of rheumatoid arthritis (RA) are influenced by environmental and genetic risk factors. Shared epitope-coding human leukocyte antigen (HLA)-DRB1 alleles increase RA risk and severity; however, the underlying mechanisms of action remain unclear. In contrast, several other DRB1 alleles protect against RA. Additionally, genome-wide association studies suggest that RA associates with other, HLA and non-HLA, genes; but the relative contributions of such risk loci to RA are incompletely understood. Future research challenges include integrating the epidemiologic and genomic data into validated arthritogenic pathways and determining the mechanisms of interaction between RA risk genes and environmental influences.

An autumn tale: geriatric rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by erosive arthritis and systemic organ involvement. The disease may affect all ages and both sexes; usually it is seen in young women aged 25-45. Recent studies have shown that RA is among the most common inflammatory disease in older age groups. While elderly-onset rheumatoid arthritis (EORA) is still discussed in the literature, it is generally accepted as a disease beginning after 65 years of age. Compared with young-onset rheumatoid arthritis (YORA), it was found that EORA had different characteristics. EORA is characterized by more equal gender distribution, higher frequency of acute onset with constitutional symptoms, more frequent involvement of large joints, and lower frequency of rheumatoid factor (RF) positivity. Earlier diagnosis, less erosive disease and less disease-modifying antirheumatic drug usage were reported as distinguishing EORA from YORA patients. These various clinical presentations may cause difficulties in diagnosis and differential diagnosis of EORA. However, different clinical and treatment approaches may be needed in these patients. In this article, the clinical and laboratory characteristics, prognosis and treatment principles of EORA will be discussed in light of recent literature data.

A reciprocal HLA-Disease Association in Rheumatoid Arthritis and Pemphigus Vulgaris

Human leukocyte antigens (HLA) have been extensively studied as being antigen presenting receptors, but many aspects of their function remain elusive, especially their association with various autoimmune diseases. Here we discuss an illustrative case of the reciprocal relationship between certain HLA-DRB1 alleles and two diseases, rheumatoid arthritis (RA) and pemphigus vulgaris (PV). RA is strongly associated with HLA-DRB1 alleles that encode a five amino acid sequence motif in the 70-74 region of the DR beta chain, called the shared epitope (SE), while PV is associated with the HLA-DRB1*04:02 allele that encodes a different sequence motif in the same region. Interestingly, while HLA-DRB1*04:02 confers susceptibility to PV, this and other alleles that encode the same sequence motif in the 70-74 region of the DR beta chain are protective against RA. Currently, no convincing explanation for this antagonistic effect is present. Here we briefly review the immunology and immunogenetics of both diseases, identify remaining gaps in our understanding of their association with HLA, and propose the possibility that the 70-74 DR beta epitope may contribute to disease risk by mechanisms other than antigen presentation.

Lack of tumor necrosis factor alpha gene polymorphism -857c/t (rs1799724) association in Pakistani rheumatoid arthritis patients

BACKGROUND

Rheumatoid arthritis (RA) is a common systemic autoimmune disease, influenced greatly by the pro-inflammatory cytokine tumor necrosis factor- alpha (TNF-α). Single nucleotide polymorphisms (SNPs) in regulatory regions of the TNF-α gene play a significant role in disease development and pathogenesis. The aim of this study was to investigate the association of TNF-α -857C/T (rs1799724) SNP with RA activity or severity in our Pakistani study group.

METHODS

The study included 134 (116 women, 18 men) patients with RA and 134 ethnically matched healthy controls (108 women, 26 men). Each patient's disease activity was measured by Disease Activity Score of 28 joints. The genotypes were determined in all included individuals following allele-specific polymerase chain reaction along with the prerequisite internal amplification controls. Statistical analysis including chi-square/Fischer exact test and one-way analysis of variance; nonparametric Kruskal-Wallis test was employed using Graphpad Prism 6 software for association study.

RESULTS

The prevalence of TNF-α -857C/T (rs1799724) polymorphism was not differentially distributed between RA patients and controls in either allele frequency, with odds ratio (95% CI) of 0.9661 (0.6714-1.390) and P-value of 0.8527, or genotype frequency with χ² of 0.5015 and P-value of 0.7782. Moreover, no correlation was found when genotype frequency distribution was analyzed with disease severity (P = 0.6321 and Kruskal-Wallis statistics of 1.098).

CONCLUSION

The study demonstrated -857C/T (rs1799724) polymorphism may not have influenced RA susceptibility in our study group. However, investigations of genetic variability influence on disease outcome in large prospective cohorts are required, so the complicated interconnection of genetic and environmental elements can be emulated for better understanding.

Shared epitope-antagonistic ligands: a new therapeutic strategy in mice with erosive arthritis

OBJECTIVE

The mechanisms underlying bone damage in rheumatoid arthritis (RA) are incompletely understood. We recently identified the shared epitope (SE), an HLA-DRB1-coded 5-amino acid sequence motif carried by the majority of RA patients as a signal transduction ligand that interacts with cell surface calreticulin and accelerates osteoclast (OC)-mediated bone damage in collagen-induced arthritis (CIA). Given the role of the SE/calreticulin pathway in arthritis-associated bone damage, we sought to determine the therapeutic targetability of calreticulin.

METHODS

A library of backbone-cyclized peptidomimetic compounds, all carrying an identical core DKCLA sequence, was synthesized. The ability of these compounds to inhibit SE-activated signaling and OC differentiation was tested in vitro. The effect on disease severity and OC-mediated bone damage was studied by weekly intraperitoneal administration of the compounds to DBA/1 mice with CIA.

RESULTS

Two members of the peptidomimetics library were found to have SE-antagonistic effects and antiosteoclast differentiation effects at picomolar concentrations in vitro. The lead mimetic compound, designated HS(4-4)c Trp, potently ameliorated arthritis and bone damage in vivo when administered in picogram doses to mice with CIA. Another mimetic analog, designated HS(3-4)c Trp, was found to lack activity, both in vitro and in vivo. The differential activity of the 2 analogs depended on minor differences in their respective ring sizes and correlated with distinctive geometry when computationally docked to the SE binding site on calreticulin.

CONCLUSION

These findings identify calreticulin as a novel therapeutic target in erosive arthritis and provide sound rationale and early structure/activity relationships for future drug design.

A small shared epitope-mimetic compound potently accelerates osteoclast-mediated bone damage in autoimmune arthritis

We have recently proposed that the shared epitope (SE) may contribute to rheumatoid arthritis pathogenesis by acting as a ligand that activates proarthritogenic signal transduction events. To examine this hypothesis, in this study we characterized a novel small SE-mimetic compound, c(HS4-4), containing the SE primary sequence motif QKRAA, which was synthesized using a backbone cyclization method. The SE-mimetic c(HS4-4) compound interacted strongly with the SE receptor calreticulin, potently activated NO and reactive oxygen species production, and markedly facilitated osteoclast differentiation and function in vitro. The pro-osteoclastogenic potency of c(HS4-4) was 100,000- to 1,000,000-fold higher than the potency of a recently described linear SE peptidic ligand. When administered in vivo at nanogram doses, c(HS4-4) enhanced Th17 expansion, and in mice with collagen-induced arthritis it facilitated disease onset, increased disease incidence and severity, enhanced osteoclast abundance in synovial tissues and osteoclastogenic propensities of bone marrow-derived cells, and augmented bone destruction. In conclusion, c(HS4-4), a highly potent small SE-mimetic compound enhances bone damage and disease severity in inflammatory arthritis. These findings support the hypothesis that the SE acts as a signal transduction ligand that activates a CRT-mediated proarthritogenic pathway.

An HLA-DRB1-coded signal transduction ligand facilitates inflammatory arthritis: a new mechanism of autoimmunity

Particular alleles of HLA contribute to disease susceptibility and severity in many autoimmune conditions, but the mechanisms underlying these associations are often unknown. In this study, we demonstrate that the shared epitope (SE), an HLA-DRB1-coded sequence motif that is the single most significant genetic risk factor for erosive rheumatoid arthritis, acts as a signal transduction ligand that potently activates osteoclastogenesis, both in vitro and in vivo. The SE enhanced the production of several pro-osteoclastogenic factors and facilitated osteoclast (OC) differentiation in mouse and human cells in vitro. Transgenic mice expressing a human HLA-DRB1 allele that code the SE motif demonstrated markedly higher propensity for osteoclastogenesis and enhanced bone degradation capacity ex vivo. In addition, the SE enhanced the differentiation of Th17 cells expressing the receptor activator for NF-κB ligand. When the two agents were combined, IL-17 and the SE enhanced OC differentiation synergistically. When administered in vivo to mice with collagen-induced arthritis, the SE ligand significantly increased arthritis severity, synovial tissue OC abundance, and bone erosion. Thus, the SE contributes to arthritis severity by activating an OC-mediated bone-destructive pathway. These findings suggest that besides determining the target specificity of autoimmune responses, HLA molecules may influence disease outcomes by shaping the pathogenic consequences of such responses.

Radiographic estimation in seropositive and seronegative rheumatoid arthritis

Long since it have been suggested that a subpopulation of patients with rheumatoid arthritis, diagnosed with negative rheumatoid factor tests, represents a clinical entity quite distinct from that of seropositive rheumatoid arthritis (RA). Our aim was to establish a scientific comparative analysis between seronegative and seropositive rheumatoid arthritis, regarding some radiological and clinical parameters, applied for the first time on patients from Kosovo. Two hundred fifty patients with rheumatoid arthritis according to the American College of Rheumatology criteria were retrospectively studied by analysis the radiographic damage and clinical parameters of the disease, using a data base. All examinees were between 25-60 years of age (Xb=49.96, SD=10.37) with disease duration between 1-27 years (Xb = 6.41, SD=6.47). All patients underwent a standardised evaluation radiographs. Baseline standardised poster anterior radiographs of hands and feet and radiographs of other joints, depending on indications, were assessed. Erythrocyte sedimentation rate values correlated with the radiological damages and statistical difference was found for seronegative subset (r=0.24, p<0.01). Longer duration of the disease resulted in the increase of radiological changes in both subsets (r=0.66, p<0.01) seronegative, (r=0.49, p<0.01) seropositive. Anatomic changes of IInd and IIIrd level were nearly equally distributed in both subsets, 76 (60.8%) seronegative, 75 (60%) seropositive. Radiological damages are nearly equal in both subsets, elevate in relation to the duration of the disease and correlate with ESR values. Regarding the sero-status, differences within sex, with some exceptions, are not relevant. Although there are some definite quantitative and qualitative differences regarding sero-status, obviously there is a great deal of overlap between the two groups.

A systematic review of serum biomarkers anti-cyclic citrullinated Peptide and rheumatoid factor as tests for rheumatoid arthritis

This systematic review assesses the current status of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) tests in the diagnosis and prognosis of rheumatoid arthritis (RA). We reviewed publications on tests and biomarkers for early diagnosis of RA from English-language MEDLINE-indexed journals and non-MEDLINE-indexed sources. 85 publications were identified and reviewed, including 68 studies from MEDLINE and 17 non-MEDLINE sources. Anti-CCP2 assays provide improved sensitivity over anti-CCP assays and RF, but anti-CCP2 and RF assays in combination demonstrate a positive predictive value (PPV) nearing 100%, greater than the PPV of either of the tests alone. The combination also appears to be able to distinguish between patients whose disease course is expected to be more severe and both tests are incorporated in the 2010 ACR Rheumatoid Arthritis Classification Criteria. While the clinical value of anti-CCP tests has been established, differences in cut-off values, sensitivities and specificities exist between first-, second- and third-generation tests and harmonization efforts are under way. Anti-CCP and RF are clinically valuable biomarkers for the diagnosis and prognosis of RA patients. The combination of the two biomarkers in conjunction with other clinical measures is an important tool for the diagnosis and management of RA patients.

A spectrum of susceptibility to rheumatoid arthritis within HLA-DRB1: stratification by autoantibody status in a large UK population

Previously-proposed rheumatoid arthritis (RA) HLA-DRB1 susceptibility and protective models were compared, based on amino acids at positions 67-74 and autoantibody combinations. 3 657 RA patients and 1 357 controls were studied using logistic regression, with secondary stratification by anti-citrullinated peptide antibodies(ACPA) and rheumatoid factor(RF). Susceptibility models were based on previously defined HLA-DRB1 shared epitope(SE) subgroups. (70)DERAA(74), D(70) and I(67) protective models were compared, adjusting for HLA-DRB1 SE. A hierarchy of risk was observed within the HLA-DRB1 SE, particularly for ACPA-positive and RF-positive RA: HLA-DRB1(*)0401∼(*)0404>(*)0101∼(*)1001 ((*)0404>(*)0101: P=0.0003). HLA-DRB1(*)0401/(*)0404 compound heterozygosity conferred a risk similar to (*)0401 homozygosity (P=0.70). Protective effects of D(70) and I(67) were similar. Predictions of the D(70) model fitted the data better than those of the I(67) model. The protective effect of D(70) showed a gene-dose effect (OR 0.82, 95% CI 0.73-0.92, P=5.8 × 10(-4)), but was only seen in RA patients positive for RF or ACPA. HLA-DRB1 SE alleles were also associated with ACPA-negative, RF-positive RA (OR 1.42 (1.15-1.76), P=0.0012). In conclusion, HLA-DRB1 SE alleles show heterogeneity in RA susceptibility; their major effect appears to be mediated by ACPA positivity, but a significant association of HLA-DRB1 SE with RF-positive, ACPA-negative RA was also observed. D(70) specifically protected against antibody-positive RA.

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.

IL10 GGC Haplotype Is Positively and HLA-DQA1*05-DQB1*02 Is Negatively Associated with Radiographic Progression in Undifferentiated Arthritis

Objective.

In rheumatoid arthritis (RA), many genetic markers, such as the shared-epitope (SE) alleles, are described in association with radiographic progression, but limited data are available on undifferentiated arthritis (UA). We investigated whether single-nucleotide polymorphisms (SNP) and haplotypes in immune response genes and HLA class II alleles are associated with radiographic progression in patients with early UA.

Methods.

Progression of radiographic damage was determined in white Dutch patients with early UA after 2 years of followup. Severe progression was defined as an increase in Sharp/van der Heijde Score ≥ 5 points after 2 years of followup. The remainder was classified as mild. These SNP were genotyped by Taqman technology: tumor necrosis factor (TNF) −1031, −863, −857, −308, −238; lymphotoxin-α (LTA) +368, +252; interleukin 10 (IL10) −2849, −1082, −819; IL1A −889, IL1B −31, +3953; and IL1RN +2018. Carriage of SE alleles and HLA-DQA1*05-DQB1*02 haplotype was established. These markers were analyzed in relation to radiographic progression.

Results.

Forty-eight out of 151 patients with early UA had severe radiographic progression. Severe radiographic progression was associated with an increased carrier frequency of SE alleles (OR 5.12, 95% CI 2.0–13.1, p < 0.001) and IL10 GGC haplotype (OR 2.8, 95% CI 1.4–5.8, p = 0.003). Mild radiographic progression was associated with the HLA-DQA1*05-DQB1*02 haplotype (OR 0.3, 95% CI, 0.1–0.8, p = 0.013) and with allele TNF −308A (OR 0.4, 95% CI, 0.2–0.9, p = 0.02).

Conclusion.

The SE and the IL10 GGC haplotype are associated with severe progression of radiographic damage, in contrast to the DQA1*05-DQB1*02 haplotype and the TNF −308A allele, which are associated with mild radiographic progression in early UA.

Combining effects of polymorphism of tumor necrosis factor α 5'-flanking region and HLA-DRB1 on radiological progression in patients with rheumatoid arthritis

We examined whether polymorphisms upstream of the TNF-α gene (TNFA) were associated with the radiological progression of rheumatoid arthritis (RA). One hundred and twenty-three patients with early RA (disease duration <1 year) were enrolled in a prospective follow-up study. The laboratory findings (ESR, CRP, and RF) were evaluated every 2 months for 2 years. Radiological progression in hands/wrists and feet was evaluated every 6 months for 2 years using Larsen's score. HLA-DRB1 genotype was determined by PCR-RFLP method. The genotypes for -1031, -863, and -857 single-nucleotide polymorphisms in the upstream 5'-flanking region of TNFA were determined by a PCR-preferential homoduplex formation assay in patients with RA and 265 healthy controls. Four TNFA alleles (U01, U02, U03, and U04) were identified. The frequency of individuals with U02 was significantly higher in patients than in controls (P = 0.0025). Radiographs of hands/wrists/feet were available for 72 patients after 1 year and for 73 patients after 2 years. When the HLA-DRB1 genotype was analyzed simultaneously, patients possessing U02 without an HLA-DRB1 shared epitope (SE) (U02+SE-) showed the lowest progression of Larsen's score (12 months). There was no difference in the level of ESR, CRP, or RF at the first visit among U02+SE+, U02+SE-, U02-SE+, and U02-SE- groups. The combination of the polymorphism of the TNFA upstream promoter region and HLA-DRB1 allele was associated with radiological progression in the early stage of RA.

Combining effects of polymorphism of tumor necrosis factor alpha 5'-flanking region and HLA-DRB1 on radiological progression in patients with rheumatoid arthritis

We examined whether polymorphisms upstream of the TNF-alpha gene (TNFA) were associated with the radiological progression of rheumatoid arthritis (RA). One hundred and twenty-three patients with early RA (disease duration <1 year) were enrolled in a prospective follow-up study. The laboratory findings (ESR, CRP, and RF) were evaluated every 2 months for 2 years. Radiological progression in hands/wrists and feet was evaluated every 6 months for 2 years using Larsen's score. HLA-DRB1 genotype was determined by PCR-RFLP method. The genotypes for -1031, -863, and -857 single-nucleotide polymorphisms in the upstream 5'-flanking region of TNFA were determined by a PCR-preferential homoduplex formation assay in patients with RA and 265 healthy controls. Four TNFA alleles (U01, U02, U03, and U04) were identified. The frequency of individuals with U02 was significantly higher in patients than in controls (P = 0.0025). Radiographs of hands/wrists/feet were available for 72 patients after 1 year and for 73 patients after 2 years. When the HLA-DRB1 genotype was analyzed simultaneously, patients possessing U02 without an HLA-DRB1 shared epitope (SE) (U02+SE-) showed the lowest progression of Larsen's score (12 months). There was no difference in the level of ESR, CRP, or RF at the first visit among U02+SE+, U02+SE-, U02-SE+, and U02-SE- groups. The combination of the polymorphism of the TNFA upstream promoter region and HLA-DRB1 allele was associated with radiological progression in the early stage of RA.

Diagnostic performance and predictive value of rheumatoid factor, anti-cyclic-citrullinated peptide antibodies and HLA-DRB1 locus genes in rheumatoid arthritis

BACKGROUND

We evaluated the significance of the genes, defined as DRB1*04 or DRB1*01, in rheumatoid arthritis (RA) patients. We focused on the role of genetic and serologic markers to predict disease activity and destructive process of joints.

METHODS

Sixty patients with RA were examined. Radiographic changes were evaluated by (Larsen score) and disease activity was measured by disease activity score 28 (DAS28). The markers analyzed were: erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-cyclic citrullinated peptides (anti-CCP2) and HLA-DRB1 alleles typed by PCR.

RESULTS

In this study, anti-CCP antibodies, CRP, RF and AKA were detected in 83.3%, 56.7%, 71.7% and 52% of patients respectively. HLA-DRB1*01 was found in 45% of patients and 35% of them had one or two HLA-DRB1*04 alleles. According to DRB1*04 subtypes, (DRB1* 0405) was present in of 80% them. For prediction of grade of activity, the independent predictors were anti-CCP (OR 19.6), and DRB1*04 positive allele (OR 5.1). The combination of DRB1*04 + anti-CCP antibodies gave increase in the specificity and positive predictive value to 92% and 90 respectively. As regards to the prediction of radiological joint damage, the independent predictors were HLA-DRB1*04, HLA-DRB1*01, RF, and CRP > 18 (OR 5.5, 4.5, 2.5, 2.0 respectively).

CONCLUSION

Our findings suggest that anti-CCP2 is superior to RF for the detection of RA and provided predictive information on joint destruction and disease activity. The presence of RA associated antibodies (ACCP or RF) and/or the SE genes are indicative for a poorer radiological outcome and higher grade of activity.

Established rheumatoid arthritis: clinical assessments

Clinical assessment of established rheumatoid arthritis (RA) can have several purposes. It can be used to evaluate prognosis, disease course or interventions at both the individual and the group level (i.e. in a clinical trial), over the short or long term. The instruments used for the different purposes are not always the same. For example, information on prognosis is very useful when assessing the risk:benefit ratio of early aggressive pharmacotherapy; however, established prognostic factors are currently of limited use in individual patients with established RA. As, at the individual patient level, disease activity, disability and joint damage have variable courses, the course of the disease should be evaluated regularly both with process (i.e. erythrocyte sedimentation rate, joint counts) and with outcome (i.e. radiological progression, sum of past process) measures. For the evaluation of interventions, 'core sets' of valid measures to assess disease activity, outcome and specific criteria for improvement are used; these can, to some extent, be useful in clinical practice.

Prognostic factors of radiographic progression in early rheumatoid arthritis: a two year prospective study after a structured therapeutic strategy using DMARDs and very low doses of glucocorticoids

The objective of the study was to analyze the prognostic factors of radiographic progression in a series of patients with early rheumatoid arthritis (RA) after 2 years of therapy with a structured algorithm using disease-modifying antirheumatic drugs (DMARDs) and very low doses of oral glucocorticoids. One hundred and five patients (81% female) with early RA (disease duration <2 years) treated with the same therapeutic protocol using gold salts and methotrexate in a step-up strategy, together with methylprednisolone (4 mg/day), were followed up for 2 years. The outcome variable was radiographic progression after 2 years of DMARD therapy using the modified Larsen method. Clinical, biological, immunogenetic, and radiographic data were analyzed at study entry and after 1 and 2 years of follow-up. Radiographic progression (increase of four or more units in the Larsen score) was observed in 32% of patients after 2 years of follow-up. The percentage of erosive disease increased from 18.3% at baseline to 28.9% at 12 months and 44.6% at 24 months, in spite of a significant improvement in disease activity. New erosions appeared in 33% of patients after 2 years. Several baseline parameters were associated with radiographic progression in the univariate analysis: shared epitope (SE) homozygozity, HLA-DRB*04 alleles, female gender, hemoglobin, erythrocyte sedimentation rate, and anticyclic citrullinated peptide antibodies (anti-CCP). In the multivariate analysis, female gender [odds ratio (OR) 5.5, 95% confidence interval (CI): 1.1-28.2, p = 0.04], DRB1*04 alleles (OR 3.1, 95% CI 1.1-9, p = 0.03) and, marginally, anti-CCP antibodies (OR 3.6, 95% CI 0.9-14.5, p = 0.06), were associated with progression. Female patients with both DRB1*04 alleles and anti-CCP antibodies showed the highest scores in radiographic progression. The presence, but not the titer, of anti-CCP antibodies predicted progression. The positive predictive value of the multivariate model for progression was only 53.9% whereas the negative predictive value was 80.3%. In a series of early RA patients treated with a structured algorithm using DMARDs and very low doses of glucocorticoids, radiographic progression was observed in one third of patients after 2 years. Female gender, DRB1*04 alleles (rather than the SE), and the presence of anti-CCP antibodies at baseline (independently of the titer) were the most important predictors of progression. The utility of these parameters in clinical practice is limited by their relatively low positive predictive value.

Antibodies to citrullinated human fibrinogen synthetic peptides in diagnosing rheumatoid arthritis

Since aggressive therapy given early in the rheumatoid arthritis (RA) disease course has the greatest therapeutic potential, early diagnostic tests with both high specificity and sensitivity are desirable. Rheumatoid sera were found to contain antibodies against citrullinated peptides, which are considered to be highly specific markers of RA. In the present work several analogues of the alpha- and beta-chains of fibrin peptides containing different degrees of citrullination have been synthesized and analyzed by ELISA using 111 sera from RA patients. In addition, we have also investigated the synergistic effects of different presentation formats of the synthetic constructs. We have designed chimeric and cyclic peptides that bear different peptide sequences within the same molecule. Our results indicate that the synthesis of peptides bearing fibrinogen and filaggrin domains could be a robust method for the design of useful diagnostic strategies in RA.

Independent associations of anti-cyclic citrullinated peptide antibodies and rheumatoid factor with radiographic severity of rheumatoid arthritis

Several recent publications have established a strong association between anti-cyclic citrullinated peptide antibody (anti-CCP)-positive rheumatoid arthritis (RA) and carriage of shared epitope (SE) alleles. Although anti-CCP have also been associated with more severe RA, the issue of whether this is independent of rheumatoid factor (RF) has not been addressed. To identify associations between RF, anti-CCP, SE status and radiological damage, we studied a large cross-sectional cohort with longstanding RA. Individuals (n = 872) enrolled in the study all fulfilled the American College of Rheumatology criteria for RA, had a minimum disease duration of 3 years, and at least one definite radiographic erosion was present in hands or feet. Radiographs were scored blind at study entry by a single musculoskeletal radiologist using a modified Larsen's score. Anti-CCP and RF levels were determined using enzyme-linked immunosorbent assay, and DRB1 typing was performed using polymerase chain reaction based methodology. Both anti-CCP and RF levels were strongly associated with radiographic severity (P < 0.0001). In subgroups stratified for both anti-CCP and RF status, evidence of independent associations of both antibodies with radiographic outcome was found (P < 0.0001). An association of SE alleles with radiographic severity was present only in RF-negative individuals. Anti-CCP positivity was associated with SE status with evidence of a gene-dose effect, most markedly in RF-negative individuals (P < 0.01). Anti-CCP and RF status are independent severity factors for RA, with SE alleles playing at most a secondary role. Our data support the view that previously described associations between SE and radiological severity, especially in RF-negative patients, may be indirect and due to an association with anti-CCP.

Rheumatoid arthritis and genetic markers in Syrian and French populations: different effect of the shared epitope

OBJECTIVE

To investigate whether ethnic differences exist in the effect of the shared epitope and selected cytokine gene polymorphisms on the susceptibility and severity of rheumatoid arthritis in Syria (Damascus) and France (Rhône-Alpes area).

METHODS

156 patients with rheumatoid arthritis and 120 healthy controls from Syria were compared with 512 patients with rheumatoid arthritis and 471 healthy controls from France. Shared epitope status, cytokine gene polymorphisms interleukin (IL)-1B +3954, IL-1RN +2018 and tumour necrosis factor alpha promoter (-238 and -308) were analysed by enzyme-linked oligosorbent assay. Joint destruction was defined by a right wrist Larsen score > or =2. Odds ratios (ORs) were calculated.

RESULTS

In both countries, a dose effect was observed between the shared epitope copy number and rheumatoid arthritis (Syria: OR 1 v 0 copies = 1.6, p = NS; OR 2 v 0 = 15.3, p<0.01; and France: OR 1 v 0 = 2.3, p<0.001; OR 2 v 0 = 7.2, p<0.001). A dose effect was also observed between the shared epitope copy number and joint destruction in Syria (OR 1 v 0 = 2.2, p = NS; OR 2 v 0 = 9.9, p<0.01) and France (OR 1 v 0 = 1.8, p<0.01; OR 2 v 0 = 4.8, p = 0.001). The dose effect of the shared epitope was greater in Syria than in France. Only the -238 tumour necrosis factor alpha polymorphism was associated with joint destruction in the Syrian population (p<0.05). However, after adjustment for age, sex, disease duration and rheumatoid factor for severity, this association disappeared.

CONCLUSION

The frequency of the shared epitope was increased in the French population with rheumatoid arthritis and in controls, but the association between the shared epitope and joint destruction was more pronounced in the Syrian population, with an OR of almost 10 for the homozygotes.

Regulation of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis: contrasting effects of HLA-DR3 and the shared epitope alleles

OBJECTIVE

To examine the association between HLA-DRB1 alleles and the production of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) autoantibodies in patients with rheumatoid arthritis (RA).

METHODS

We studied 1,723 Caucasian RA patients enrolled in the North American Rheumatoid Arthritis Consortium (NARAC) family cohort and the Study of New Onset Rheumatoid Arthritis (SONORA) cohort. All patients were tested for anti-CCP antibodies (by enzyme-linked immunosorbent assay), RF (by nephelometry), and HLA-DR genotype (by polymerase chain reaction and sequence-specific oligonucleotide hybridization).

RESULTS

When controlled for the presence of RF, anti-CCP positivity was strongly associated with the HLA-DRB1 shared epitope (SE). In RF+ patients, the presence of the SE was very significantly associated with anti-CCP positivity, with an odds ratio (OR) of 5.8 and a 95% confidence interval (95% CI) of 4.1-8.3. This relationship was also seen in RF- patients (OR 3.1 [95% CI 1.8-5.3]). In contrast, RF positivity was not significantly associated with presence of the SE independently of anti-CCP antibodies. Strikingly, HLA-DRB1*03 was strongly associated with reduced anti-CCP titers, even after controlling for the presence of the SE and restricting the analysis to anti-CCP+ patients. HLA-DR3 was also associated with anti-CCP- RA in our population.

CONCLUSION

The HLA-DRB1 SE is strongly associated with the production of anti-CCP antibodies, but not RF. In contrast, HLA-DR3 alleles are associated with anti-CCP- disease and with lower levels of anti-CCP antibodies, even when controlling for the SE. These data emphasize the complexity of the genetic effects of the major histocompatibility complex on the RA phenotype.

Association of tumor necrosis factor α polymorphism, but not the shared epitope, with increased radiographic progression in a seropositive rheumatoid arthritis inception cohort

OBJECTIVE

To determine whether the tumor necrosis factor alpha (TNFA) -308 guanine-to-adenosine polymorphism and/or the shared epitope (SE) is associated with radiographic damage in patients with early rheumatoid arthritis (RA).

METHODS

The cohort consisted of 189 patients with early seropositive RA (median 5.6 months since symptom onset) who had active disease, no previous disease-modifying antirheumatic drug treatment, and >or=2 sets of scored radiographs of the hands/wrists and forefeet. TNFA -308 polymorphism was analyzed by polymerase chain reaction pyrosequencing. The SE was defined as presence of any 1 of the following HLA-DRB1 alleles: *0101, *0102, *0401, *0404, *0405, *0408, *0410, *1001, *1402, or *1406. Radiographic progression was assessed by the total Sharp score.

RESULTS

Using a weighted least-squares regression analysis, patients with the -308 TNFA AA plus AG genotypes (n=49) had significantly higher rates of progression in erosion scores (median 0.84 versus 0.48 units/year), joint space narrowing (JSN) scores (0.42 versus 0.04), and total Sharp scores (1.70 versus 0.61) compared with patients with the TNFA GG genotype (n=140). Presence of the SE (n=137) was associated with significantly lower progression rates (per year) for total Sharp scores (median 0.9 versus 1.25 units/year) and JSN scores (0.04 versus 0.41), but not for erosion scores (0.50 versus 0.61) compared with patients without the SE (n=52). In a least-squares multiple linear regression model, the presence of the AA plus AG genotypes was associated with a significantly higher progression rate after adjusting for the presence of the SE, interaction between the SE and the AA plus AG genotypes, baseline log C-reactive protein level, Health Assessment Questionnaire Disability Index, total Sharp score, swollen joint count, and presence of osteophytes (osteoarthritis). There was a strong linkage disequilibrium between DRB1*0301 and TNFA polymorphism (D'=0.84, r2=0.45, P<0.001).

CONCLUSION

This study showed an association between the TNFA -308 polymorphism and progression of radiographic damage in patients with early seropositive RA. This association appeared to be independent of the SE, but might be dependent on other genetic variants in linkage disequilibrium with the -308 TNFA A allele and DRB1*0301. Further studies should be conducted to validate these results in both longitudinal observational cohorts and randomized clinical trials.

Tumor necrosis factor-alpha -308 promoter polymorphism contributes independently to HLA alleles in the severity of rheumatoid arthritis in Mexicans

The aim of this study was to determine the frequency and potential relevance of the promoter polymorphisms of the tumor necrosis factor-alpha (TNF-alpha) in the severity of rheumatoid arthritis (RA) in Mexicans. HLA-DR and polymorphisms at positions -238 and -308 of TNF-alpha gene were determined in 137 Mexican RA patients (44 with severe and 93 with non-severe RA) as well as in 169 healthy controls (99 were typed for HLA-DR). We observed an increased frequency of HLA-DR4 in severe RA compared to healthy controls (pC=0.02, OR=2.33). TNF polymorphism analysis showed a significant increased frequency of TNF -238 GG genotype in the whole group of RA patients when compared to healthy controls (pC=0.007, OR=4.71). When the analyses were carried out separately in severe and non-severe RA patients, the increased frequency of -238 GG genotype only was observed in patients with non-severe forms of the disease. Analysis of -308 polymorphism showed increased frequency of -308 T2 (A) allele in severe RA when compared to non-severe disease (pC=0.011, OR=3.29) and to healthy controls (pC=0.002, OR=3.97). The data demonstrate that -308 T2 (A) allele is associated with susceptibility to develop severe RA in Mexicans. This association could be independent from HLA-DR alleles and might be used as a prognostic marker for severe RA.

Physical examination and laboratory tests in the management of patients with rheumatoid arthritis: development of recommendations for clinical practice based on published evidence and expert opinion

OBJECTIVES

To develop recommendations for the physical and laboratory-test follow-up of patients with rheumatoid arthritis (RA) seen in everyday practice, using evidence from the literature, supplemented with expert opinion when needed.

METHODS

A scientific committee selected 7-10 questions using the Delphi consensus procedure. Evidence-based responses to each question were sought in the literature and were then used by a panel to develop recommendations. To fill in gaps in knowledge from the literature, the panelists relied on their personal opinion.

RESULTS

The seven questions dealt with the physical and laboratory-test follow-up of RA and the factors predicting disease severity. The literature review identified 799 articles whose title and abstract suggested relevance to the study. Elimination of articles that provided no data on the study topic left 128 original articles. The panel developed seven recommendations, one for each question, which were accepted by consensus.

CONCLUSION

Recommendations about the physical and laboratory-test follow-up of patients with RA seen in everyday practice were developed. Because they constitute an objective foundation built by consensus among experts, should improve the uniformity and quality of care provided to RA patients in everyday practice.

Is there a future for TNF promoter polymorphisms?

The in vitro study of TNF promoter polymorphism (SNP) function was stimulated by the numerous case-control (association) studies of the polymorphisms in relation to human disease and the appearance of several studies claiming to show a functional role for these SNPs provided a further impetus to researchers interested in the role of TNF in their disease of interest. In this review we consider case-control studies, concentrating on the autoimmune and inflammatory diseases rheumatoid arthritis, multiple sclerosis, ankylosing spondylitis, and asthma, and on infectious diseases including malaria, hepatitis B and C infection, leprosy and sepsis/septic shock. We also review the available evidence on the functional role of the various TNF promoter polymorphisms. In general, case-control studies have produced mixed results, with little consensus in most cases on whether any TNF polymorphisms are actually associated with disease, although results have been more consistent in the case of infectious diseases, particularly malaria. Functional studies have also produced mixed results but recent work suggests that the much studied -308G/A polymorphism is not functional, while the function of other TNF polymorphisms remains controversial. Studies of the TNF region are increasingly using extended haplotypes that can better capture the variation of the MHC region.

Rheumatoid factor and anticitrullinated protein antibodies in rheumatoid arthritis: diagnostic value, associations with radiological progression rate, and extra-articular manifestations

BACKGROUND

Autoantibodies such as rheumatoid factor (RF) and anticitrullinated protein antibodies can be detected in rheumatoid arthritis (RA) sera.

OBJECTIVE

To determine the diagnostic values of RF, anticitrullinated protein antibodies, and the shared epitope (SE), and their associations with radiological progression rates and extra-articular manifestations.

METHODS

Population 1 consisted of sera from 315 patients, consecutively sent for detection of anticitrullinated protein antibodies, of which 264 were used to determine the sensitivity and specificity of RF and of antibodies against three synthetic citrullinated peptides: peptide A (pepA), peptide B (pepB), and CCP2. Population 2 consisted of sera from 180 longstanding RA patients and was used to determine associations of RA associated antibodies and the SE with radiological progression rates and extra-articular manifestations. Antibodies to pepA and pepB were detected by line immunoassay, and antibodies to CCP2 by ELISA. HLA Class II typing was performed by LiPA.

RESULTS

In population 1, we defined adapted cut offs corresponding to a specificity of >/=98.5%. This yielded the following sensitivities: RF 12.8%; anti-pepA antibodies 63.6%; anti-pepB antibodies 54.2%; and anti-CCP2 antibodies 73.7%. In population 2, significant differences in radiological progression rates were found between positive and negative patients for different RA antibodies and the SE. RF, but not anticitrullinated protein antibodies or the SE, were more frequent in patients with extra-articular manifestations.

CONCLUSION

A valid comparison of RA associated antibodies shows superior sensitivity of the anticitrullinated protein antibodies compared with RF. The presence of RA associated antibodies and the SE are indicative for poorer radiological outcome, and presence of extra-articular manifestations is associated with RF but not with anticitrullinated protein antibodies.

Interaction between RANKL and HLA-DRB1 genotypes may contribute to younger age at onset of seropositive rheumatoid arthritis in an inception cohort

OBJECTIVE

To determine whether the RANKL and HLA-DRB1 "shared epitope" (SE) genotypes contribute to the development of rheumatoid arthritis (RA).

METHODS

We studied 237 patients with early RA (within 15 months of symptom onset) who were seropositive for rheumatoid factor. HLA-DRB1 genotyping was performed using the polymerase chain reaction (PCR)-based oligonucleotide probe assay. RANKL polymorphisms were analyzed using PCR pyrosequencing for SNP1 and fluorescence-based PCR for the presence or absence of the TAAA insertion.

RESULTS

The presence of SE-containing DRB1*04 alleles was associated with an earlier age at RA onset (mean +/- SD 47 +/- 12.7 years versus 53 +/- 12.5 years in SE- patients; P = 0.0004). The 2 novel RANKL polymorphisms were in strong linkage disequilibrium (P < 0.0001) and were associated with earlier ages at disease onset (e.g., for the CC versus CT/TT genotypes, 44 +/- 13.5 years versus 51 +/- 12.7 years; P = 0.0080). The mean age at disease onset in SE+ patients with the RANKL-CC genotype (35 +/- 7.2 years) was a mean of 18 years younger than in SE- patients with RANKL-CT/TT (53 +/- 12.5 years; P < 0.0001) and was 17 years younger than in SE- patients with RANKL-CC (52 +/- 13.2 years; P = 0.0005). The proportion of patients with both the SE and RANKL risk alleles was highest (23%) in those who developed RA during their third decade of life (ages 20-30 years), with a declining trend among those who developed RA during their fourth (16%), fifth (5%), and sixth or later (0%) decades. Interestingly, 92% of the patients diagnosed as having RA between ages 20 and 30 years carried at least 1 of the RA-associated DRB1*04 alleles, suggesting a strong influence of the SE in the early onset of RA. The majority of patients who developed RA symptoms in their third to fifth decades (74 of 119 [62%]) carried at least 1 copy of the DRB1*04 alleles; in contrast, fewer than half of the patients who developed RA in their sixth decade or later (50 of 118 [42%]) had DRB1*04 alleles. RANKL genotypes were not associated with erosive disease at baseline or with the yearly progression rate of radiographic joint damage.

CONCLUSION

This study provides the first evidence that novel RANKL polymorphisms were associated with an earlier age at RA onset in SE+, but not SE-, patients and that an interaction between SE-containing HLA-DRB1 and RANKL polymorphisms increased the disease penetrance, resulting in a mean age at RA onset that was 18-20 years younger. Our results also suggested genetic differences between patients with early-onset and those with late-onset RA.

Prediction of radiological outcome in early rheumatoid arthritis in clinical practice: role of antibodies to citrullinated peptides (anti-CCP)

OBJECTIVE

To investigate the role of anti-cyclic citrullinated peptide antibody (anti-CCP) for the prediction of radiological outcome in patients with early rheumatoid arthritis.

METHODS

Anti-CCP was assessed at baseline in 379 patients with early rheumatoid arthritis (disease duration <1 year). Radiological joint damage and progression were assessed by Larsen score after two years of follow up (end point) and used as outcome variables. The prognostic value of anti-CCP and other demographic and disease related baseline variables were assessed by univariate and multivariate analyses, including calculation of odds ratios (OR), predictive values, and multiple logistic regression models.

RESULTS

The presence of anti-CCP was associated with significantly higher Larsen score both at baseline and at end point. Univariate predictor analysis showed that anti-CCP had the highest significant OR for radiological joint damage and progression after baseline Larsen score, followed by rheumatoid factor, erythrocyte sedimentation rate (ESR), C reactive protein, age, smoking status, and sex. In stepwise multiple regression analyses, baseline Larsen score, anti-CCP, and ESR were selected as significant independent predictors of the radiological outcomes.

CONCLUSIONS

There is good evidence for an association of anti-CCP with radiological joint changes in rheumatoid arthritis. Anti-CCP is an independent predictor of radiological damage and progression. Though prediction in early rheumatoid arthritis is still far from perfect, the use of anti-CCP in clinical practice should make it easier for rheumatologists to reach judicious treatment decisions.

Association of a specific haplotype across the genes MMP1 and MMP3 with radiographic joint destruction in rheumatoid arthritis

The genetic background of rheumatoid arthritis (RA) is only partly understood, and several genes seem to be involved. The matrix metalloproteinases MMP1 (interstitial collagenase) and MMP3 (stromelysin 1) are thought to be important in destructive joint changes seen in RA. In the present study, functional relevant promoter polymorphisms of MMP1 and MMP3 were genotyped in 308 patients and in 110 controls, to test whether the polymorphisms contribute to the severity of the disease measured by radiographic progression of joint destruction. For comparison, the shared epitope of HLA DR4 and DR1 (SE) was determined by polymerase chain reaction. There was no association of MMP polymorphisms with susceptibility to RA. However, a strong linkage disequilibrium was observed between the 1G/2G (MMP1) and the 5A/6A (MMP3) polymorphisms (P << 10^-6; linkage disequilibrium index D' = 0.46). In factorial regression, the degree of radiographic joint destruction correlated significantly with the 1G-5A haplotype (P = 0.0001) and the interaction term 'estimated number of 1G-5A haplotypes × duration of disease' (P = 0.0007). This association was phasic, indicating that possession of the 1G-5A haplotype has a protective effect over a period of about 15 years of RA, but might be associated with a more pronounced radiographic progression later on. Similar results were also found with the 1G allele of MMP1 alone (P = 0.015) and with the interaction term 'estimated number of 1G alleles × duration of disease' (P = 0.014). The correlation of SE with the Ratingen score was comparable (0.044). The regression model of MMP haplotypes explained 35% of the variance of the radiographic score, whereas the SE explained 29%. The 1G-5A haplotype across the closely linked MMP1 and MMP3 gene loci is a newly described genetic factor strongly associated with the progression of joint damage in RA. Our findings suggest that there are haplotypes in a MMP cluster region that modify the joint destruction in RA in a phasic manner.

Approaches to identifying genetic predictors of clinical outcome in rheumatoid arthritis

Predicting which patients with rheumatoid arthritis (RA), at presentation, are likely to suffer a severe disease course based on genotype data would be a major clinical advance. It would ensure that patients at highest risk of a severe outcome could be targeted with early aggressive therapies. With a better understanding of interactions between genotype and drug response it would be possible to prescribe treatments most likely to be efficacious and safe for specific patient subgroups. While a clear genetic component has been demonstrated in RA severity, the identification of genetic factors poses a challenge to researchers in the field. Initiatives such as the SNP Consortium and advances in genotyping technology have facilitated the investigation of genetic factors in both disease susceptibility and severity. However, several other factors, such as the availability of suitable longitudinal cohorts, definition of outcome measures, study design, selection of genetic markers, and statistical power, will all contribute to the likely success of genetic studies. Several strategies that have been applied in the pursuit of genetic predictors of clinical outcome in RA. While some encouraging results have been generated, it has so far been difficult to quantify the predictive value of genetic markers and extrapolate the results from genetic studies to clinic patients. Establishing high quality prospective inception cohorts, a more systemic approach to defining suitable outcome measures, and understanding the effects of treatment, will be critical to the eventual identification of good predictive genetic markers.

Clinical epidemiology: diagnostic and prognostic tests

Recent studies of diagnostic and prognostic tests have commonly examined serological tests and new imaging techniques. Antifilaggrin antibodies have been found to be highly specific for the diagnosis of rheumatoid arthritis (RA), but uncertainty remains about the sensitivity of this test, particularly in early RA. Magnetic resonance imaging and ultrasound continue to be explored as methods to detect synovitis and erosions in RA. Several recent studies have confirmed the association between the human leukocyte antigen DRB1 shared epitope and worse radiographic outcomes in patients with RA. Interlaboratory variation in detecting autoantibodies remains a concern, as does overuse of tests for antineutrophil cytoplasmic autoantibodies.

Genetic epidemiology of rheumatoid arthritis

Building on the spectacular success of molecular genetics in defining the biological basis of many rare single gene disorders over the past decade, epidemiologists have turned their attention to unravelling the complex genetic mysteries of common disorders, such as rheumatoid arthritis (RA). As a prelude to any such endeavour it is obviously important to establish that there is a significant genetic component to the disease. The classical approaches of twin and other family recurrence risk studies, coupled with prevalence studies in different ethnic and migrant populations, have been used to estimate the environmental and genetic contributions to RA. However, developing a consensus on these estimates has proved difficult, thereby providing an early warning to the unwary investigator that the road to gene discovery in RA is likely to be a rough ride.

HLA-DRB1 genotype associations in 793 white patients from a rheumatoid arthritis inception cohort: frequency, severity, and treatment bias

OBJECTIVE

The HLA-DRB1 "shared epitope" (SE) genotypes are associated with rheumatoid arthritis (RA), but it remains controversial whether the association is with incidence, severity, or both, whether there are associations in seronegative patients, and whether different DRB1 alleles that contain the SE have similar effects on RA susceptibility and/or severity. The present study was undertaken to study these issues in a large cohort of patients with RA.

METHODS

White patients with RA of <6 months' duration (n = 793) were enrolled in an inception cohort. HLA-DRB1 typing was performed, and patients were categorized into 21 DRB1 genotype groups. The disability index of the Health Assessment Questionnaire was the primary outcome measure.

RESULTS

DRB1 associations in seronegative RA patients closely resembled those in controls. Of seropositive patients, 21% had 2 copies of the epitope, 52% had 1 copy, and 27% had none. However, not all genotypes with 1 copy were associated with increased susceptibility; for example, frequencies of DRB1*0404/X and *01/X did not differ from those in controls. Absolute differences between seropositive RA patients and controls were greatest for DRB1*0401 homozygosity (3.8% versus 0.8%, respectively) and *0401/0404 heterozygosity (4.7% versus 1.0%). DRB1*0404 was increased in frequency in seropositive RA but, unlike *0401, an increased frequency was seen only with 2 epitope copies. The relatively rare DRB1*10 had an unexpected association with seropositive RA, being present in 1.7% of seropositive RA patients and 0.7% of controls, and also showed a trend toward association with greater disease severity. The presence of 2 epitope copies was associated with increased frequency of seropositivity and younger age at disease onset, not with disease severity. Treatment indication bias was substantial and may have accounted for some of these effects. HLA-DRB1*0401/0404 was found much more frequently in men and in patients with a lower age at disease onset, and there was a trend toward a higher frequency of *0404/0401 in women.

CONCLUSION

This large inception cohort study confirms previously identified major associations and provides additional insights. Only one dominant association was found: *0401, which differs from other SE alleles in a single Lys-for-Arg substitution. The association of the rare DRB1*10 allele has not previously been postulated. Sex associations were confirmed. Associations with seronegative RA were not seen. Not all genotypes containing an SE copy showed increased susceptibility to RA. The association of SE genotypes found in this study related to disease susceptibility rather than severity.

Relationship among the HLA-DRB1 shared epitope, smoking, and rheumatoid factor production in rheumatoid arthritis

OBJECTIVE

Rheumatoid factor (RF) production in rheumatoid arthritis (RA) is generally associated with more severe disease. In some studies, RF production has been associated with carriage of HLA-DRB1 alleles encoding the RA-associated shared epitope (SE). Patients who smoke are also more likely to be RF positive. In this study, we investigated whether the association between RF production and smoking was influenced by carriage of the SE.

METHODS

The smoking histories of 371 RA patients attending a hospital clinic were recorded. RF levels and SE status were determined for every patient, and the associations between the SE, smoking, and RF production were examined. HLA-DRB1 typing was performed using polymerase chain reaction. Results were analyzed using chi-square tests and logistic regression analysis.

RESULTS

Patients who had ever smoked were significantly more likely to be RF positive than nonsmokers (odds ratio 2.2, P < 0.0001). This remained significant (P = 0.003) after correction for age, sex, and disease duration in a logistic regression model. An association was also found between RF positivity and carriage of the SE (P = 0.03, after correction for age, sex, and disease duration), but significance was reduced or lost after correction for previous or current smoking (P = 0.05 and 0.09, respectively). Examination of the major SE phenotypes in this RA population by multivariate logistic regression analysis revealed that only DRB1*0401 was associated with RF positivity, and that this was independent of the influence of smoking.

CONCLUSION

Our data confirm that RF production in RA patients is associated with smoking. This does not appear to depend on an HLA-DR-restricted immune response. The association of the SE with RF positivity is primarily due to HLA-DRB1*0401. This appears to be independent of the association with smoking, although smoking further increases the likelihood of RF production in DRB1*0401 patients.

Heterogeneity between men and women in the influence of the HLA-DRB1 shared epitope on the clinical expression of rheumatoid arthritis

OBJECTIVE

To test the hypothesis that the influence of the HLA-DRB1 shared epitope (SE) on the clinical manifestations of rheumatoid arthritis (RA) differs between men and women.

METHODS

We assessed 777 consecutive RA patients for age at disease onset, articular manifestations, subcutaneous nodules, laboratory and radiographic findings, and treatment received. We typed HLA-DRB1 alleles by polymerase chain reaction-sequence-specific primer amplification and categorized the number of SE-containing alleles. We used regression models to adjust comparisons between the sexes for age and clustering by recruitment center, and included SE x sex interaction terms to look for heterogeneity between men and women in the effect of the SE.

RESULTS

Among the 777 RA patients, 548 (71%) were women. Men and women differed significantly in the adjusted frequency of SE positivity (women 71.4% versus men 78.4%; P < or = 0.001). The SE was associated with a younger age at symptom onset and RA diagnosis among men, but not among women. The SE likewise had a significant adverse effect on joint tenderness, swelling, and deformity among men only. The SE was associated with a higher erythrocyte sedimentation rate in women and more frequent positivity for rheumatoid factor among both men and women.

CONCLUSION

There is heterogeneity between men and women in the effect of the SE on RA susceptibility and clinical expression. Further research is needed to understand the mechanism of this heterogeneity.