ACPA-negative RA Research Articles

An autoantibody profile identified by human genome-wide protein arrays in rheumatoid arthritis.

Precise diagnostic biomarkers of anticitrullination protein antibody (ACPA)-negative and early-stage RA are still to be improved. We aimed to screen autoantibodies in ACPA-negative patients and evaluated their diagnostic performance. The human genome-wide protein arrays (HuProt arrays) were used to define specific autoantibodies from the sera of 182 RA patients and 261 disease and healthy controls. Statistical analysis was performed with SPSS 17.0. In Phase I study, 51 out of 19,275 recombinant proteins covering the whole human genome were selected. In Phase II validation study, anti-ANAPC15 (anaphase promoting complex subunit 15) exhibited 41.8% sensitivity and 91.5% specificity among total RA patients. There were five autoantibodies increased in ACPA-negative RA, including anti-ANAPC15, anti-LSP1, anti-APBB1, anti-parathymosin, and anti-UBL7. Anti-parathymosin showed the highest prevalence of 46.2% (p=0.016) in ACPA-negative early stage (<2 years) RA. To further improve the diagnostic efficacy, a prediction model was constructed with 44 autoantibodies. With increased threshold for RA calling, the specificity of the model is 90.8%, while the sensitivity is 66.1% (87.8% in ACPA-positive RA and 23.8% in ACPA-negative RA) in independent testing patients. Therefore, HuProt arrays identified RA-associated autoantibodies that might become possible diagnostic markers, especially in early stage ACPA-negative RA.

Patients with obesity have more inflamed joints and higher CRP levels during the disease course in ACPA-positive RA but not in ACPA-negative RA

BackgroundObese RA patients have higher disease activity scores (DAS). Previous research showed that obese RA patients have higher tender joint count (TJC) and VAS general health. However, it remains unclear whether DAS components measuring local and systemic inflammation (swollen joint count (SJC), CRP) are increased and if this is present in the total RA population or confined to an ACPA subgroup. As ACPA is suggested to enhance inflammatory responses, we hypothesized that the association of obesity with SJC and CRP is present especially in ACPA-positive RA. We therefore studied associations of obesity with courses of DAS components in ACPA subgroups.MethodsWe studied 649 RA patients (291 ACPA-positive), included in the Leiden Early Arthritis Clinic. Five-year courses of DAS44 and DAS44 components (SJC—44, TJC—53, CRP, VAS (0–100)) were compared between RA patients with normal weight (BMI 18.5–24.9), overweight (25.0–29.9), and obesity (≥ 30.0), stratified for ACPA. Linear/Poisson mixed models with a knot at 4 months were used.ResultsObese RA patients had + 0.32 higher DAS compared to normal weight during the 5-year follow-up. In ACPA-positive RA, obese patients had + 0.43 (95% CI: 0.22, 0.64) higher DAS, whereas in ACPA-negative RA, this difference was smaller and not statistically significant: + 0.19 (95% CI: − 0.01, 0.38). In ACPA-positive RA, all DAS components were significantly higher in obese patients compared to normal weight: SJC + 60% (IRR1.60; 95% CI: 1.18, 2.16), CRP + 3.7 mg/L (95% CI:0.95, 6.53), TJC + 55% (IRR1.55; 95% CI:1.15, 2.10), and VAS + 9 (95% CI: 4.0, 14.2). ACPA-negative obese RA patients tended to have higher TJC (IRR1.22; 95% CI: 0.96, 1.55) and VAS (β4.3; 95% CI: − 0.4, 9.0), while SJC (IRR1.07; 95% CI:0.85, 1.33) and CRP (β0.24; 95% CI: − 1.29, 3.32) were unaffected.ConclusionThe association of obesity with a worse DAS course is mainly present in ACPA-positive RA; especially SJC and CRP levels remain higher in ACPA-positive RA patients with obesity but not ACPA-negative RA patients. This is the first demonstration that obesity influences the disease course of ACPA-positive and ACPA-negative RA differently.

Patient burden and joint inflammation during development of RA from arthralgia: is it similar in ACPA-positive and ACPA-negative disease?

ACPA-positive and ACPA-negative RA differ in underlying risk factors but have a similar clinical presentation at RA diagnosis. It is unknown what the ACPA-associated differences or similarities are during the symptomatic at-risk stage of RA, i.e. clinically suspect arthralgia (CSA). To deepen insights into these differences/similarities, we compared the course of symptoms/impairments and subclinical joint inflammation in the CSA phase during progression to inflammatory arthritis (IA) or to CSA resolution. A total of 845 CSA patients were followed for a median of 24 months; 136 patients developed IA and an additional 355/505 patients had resolution of CSA according to rheumatologists. Patient burden (pain, morning stiffness, fatigue, functional disabilities, presenteeism) was assessed at baseline and 4, 12 and 24 months and at IA development. Subclinical joint inflammation in the hands and feet was assessed over time with 1.5T MRI. Linear and Poisson mixed models were used. In both ACPA-positive and ACPA-negative patients, patient burden increased towards IA development and decreased towards CSA resolution. However, patient burden was lower in ACPA-positive vs ACPA-negative disease at all timepoints. Conversely, subclinical joint inflammation tended to increase more rapidly during development of ACPA-positive IA [incidence rate ratio (IRR) 1.52 (95% CI 0.94, 2.47), P = 0.089] and remained higher over time in ACPA-positive CSA patients achieving resolution compared with ACPA-negative patients [IRR 1.52 (95% CI 1.07, 2.15), P = 0.018]. Although correlation coefficients between changes in patient burden and subclinical joint inflammation during progression to IA were weak, they were consistently higher in ACPA-positive than ACPA-negative disease, e.g. ρ = 0.29 vs 0.12 for functional disabilities. During RA development and CSA resolution, ACPA-positive CSA patients have lower patient burden but more subclinical joint inflammation than ACPA-negative CSA patients. These data strengthen the notion that the development of ACPA-positive and ACPA-negative RA is pathophysiologically different and encourage further research on these differences.

Improving our understanding of the paradoxical protective effect of obesity on radiographic damage: a large magnetic resonance imaging-study in early arthritis.

Obesity conveys a risk for RA development, while paradoxically, associating with less radiographic progression after RA diagnosis. Using MRI we can study this surprising association in detail from MRI-detected synovitis and osteitis to MRI-detected erosive progression, which precedes radiographic progression. Previous research suggested obesity associates with less osteitis and synovitis. We therefore aimed to (i) validate the previously suggested association between BMI and MRI-detected osteitis/synovitis; (ii) study whether this is specific for ACPA-positive or ACPA-negative RA or also present in other arthritides; (iii) study whether MRI-detected osteitis associates with MRI-detected erosive progression; and (iv) study whether obesity associates with MRI-detected erosive progression. We studied 1029 early arthritis patients (454 RA, 575 other arthritides), consecutively included in Leiden Early Arthritis Clinic. At baseline patients underwent hand-and-foot MRI that were RAMRIS-scored, and 149 RA patients underwent follow-up MRIs. We studied associations between baseline BMI and MRI-detected osteitis/synovitis (using linear regression), and erosive progression (using Poisson mixed models). In RA, higher BMI associated with less osteitis at disease onset (β = 0.94; 95% CI: 0.93, 0.96) but not with synovitis. Higher BMI associated with less osteitis in ACPA-positive RA (β = 0.95; 95% CI: 0.93, 0.97), ACPA-negative RA (β = 0.97; 95% CI: 0.95, 0.99) and other arthritides (β = 0.98; 95% CI: 0.96, 0.99). Over 2 years, overweight and obesity associated with less MRI-detected erosive progression (P = 0.02 and 0.03, respectively). Osteitis also associated with erosive progression over 2 years (P < 0.001). High BMI relates to less osteitis at disease onset, which is not confined to RA. Within RA, high BMI and less osteitis associated with less MRI-detected erosive progression. This suggests that the protective effect of obesity on radiographic progression is exerted via a path of less osteitis and subsequently fewer MRI-detected erosions.

Raman spectroscopy as a promising diagnostic method for rheumatoid arthritis.

Background: Diagnosis of rheumatoid arthritis (RA) basically relies on clinical symptoms and autoantibodies, especially anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor (RF). However, the lack of autoantibodies is still a dilemma clinically in seronegative RA, especially in the early stage of the disease. This study aimed to provide a unique disease fingerprint with high diagnostic value to discriminate RA based on Raman spectroscopy. Methods: Raman spectroscopy provides a repertoire of biomolecules in serum from RA. Multivariate dimension-reducing methods and machine-learning algorithms were exploited to reveal the intrinsic differences and the potential discrimination power. The underlying differential biomolecules were retrieved by the assignment of Raman peaks. Moreover, the correlations between the spectral differences and RA patient's clinical and immunological manifestations were also analyzed. Results: RA patients exhibited unique Raman spectra characterized by biomolecular alterations during the disease progression. The discrimination power yielded 97.3% sensitivity and 94.8% specificity for RA diagnosis. In the recognition of ACPA-negative RA, the sensitivity and specificity also reached 95.6% and 92.8%, respectively. In particular, the differential Raman spectrum peaks of RA patients mainly represented lipids, amino acids, glycogen, and fatty acids. Further analysis showed that the different serum Raman spectra correlated with the clinical features of RA, including disease duration, RF, anticyclic citrullinated peptide antibodies (anti-CCPs), IgA, IgM, IgG, tender joint count, and swollen joint count (|rs| = 0.15-0.52, p < 0.05). Conclusions: Raman spectroscopy was revealed to be a promising diagnostic method for RA, especially for ACPA-negative patients.

ACPA-negative and ACPA-positive RA patients achieving disease resolution demonstrate distinct patterns of MRI-detected joint-inflammation.

Although sustained DMARD-free remission (SDFR; sustained absence of clinical-synovitis after DMARD-discontinuation) is increasingly achievable in RA, prevalence differs between ACPA-negative (40%) and ACPA-positive RA (5-10%). Additionally, early DAS remission (DAS4months<1.6) is associated with achieving SDFR in ACPA-negative, but not in ACPA-positive RA. Based on these differences, we hypothesized that longitudinal patterns of local tissue inflammation (synovitis/tenosynovitis/osteitis) also differ between ACPA-negative and ACPA-positive RA patients achieving SDFR. With the ultimate aim being to increase understanding of disease resolution in RA, we studied MRI-detected joint inflammation over time in relation to SDFR development in ACPA-positive RA and ACPA-negative RA. A total of 198 RA patients (94 ACPA-negative, 104 ACPA-positive) underwent repeated MRIs (0/4/12/24months) and were followed on SDFR development. The course of MRI-detected total inflammation, and synovitis/tenosynovitis/osteitis individually were compared between RA patients who did and did not achieve SDFR, using Poisson mixed models. In total, 174 ACPA-positive RA patients from the AVERT-1 were studied as ACPA-positive validation population. In ACPA-negative RA, baseline MRI-detected inflammation levels of patients achieving SDFR were similar to patients without SDFR but declined 2.0 times stronger in the first year of DMARD treatment [IRR 0.50 (95% CI; 0.32, 0.77); P < 0.01]. This stronger decline was seen in tenosynovitis/synovitis/osteitis. In contrast, ACPA-positive RA-patients achieving SDFR, had already lower inflammation levels (especially synovitis/osteitis) at disease presentation [IRR 0.45 (95% CI; 0.24, 0.86); P = 0.02] compared with patients without SDFR, and remained lower during subsequent follow-up (P = 0.02). Similar results were found in the ACPA-positive validation population. Compared with RA patients without disease resolution, ACPA-positive RA patients achieving SDFR have less severe joint inflammation from diagnosis onwards, while ACPA-negative RA patients present with similar inflammation levels but demonstrate a stronger decline in the first year of DMARD therapy. These different trajectories suggest different mechanisms underlying resolution of RA chronicity in both RA subsets.

Unraveling heterogeneity within ACPA-negative rheumatoid arthritis: the subgroup of patients with a strong clinical and serological response to initiation of DMARD treatment favor disease resolution

BackgroundRheumatoid arthritis (RA) is a heterogeneous disease, as evidenced by the differences in long-term outcomes. This applies especially to anti-citrullinated protein antibodies (ACPA)-negative RA, where a proportion achieves sustained DMARD-free remission (SDFR; sustained absence of synovitis after DMARD cessation). Differentiation of RA patients who will achieve SDFR can guide personalized treatment/tapering strategies. Although this subgroup remains scarcely discerned, previous research demonstrated that these RA patients are characterized by an early clinical response (DAS remission after 4 months) after DMARD start. We studied whether, in addition to this clinical response, a specific biomarker response can further distinguish the subgroup of RA patients most likely to achieve SDFR.MethodsIn 266 RA patients, levels of 12 biomarkers (SAA/CRP/MMP-1/MMP-3/resistin/leptin/IL-6/TNF-R1/YKL-40/EGF/VEGF/VCAM-1), in the first 2 years after diagnosis, were studied in relation to SDFR, stratified for ACPA status. Subsequently, biomarkers associated with SDFR development were combined with early DAS remission to study its additional value in defining subgroups. Since most biomarker levels are not routinely measured in clinical practice, we explored how this subgroup can be clinically recognized.ResultsACPA-negative RA patients achieving SDFR were characterized by high baseline levels and stronger decline in MMP-1/MMP-3/SAA/CRP after DMARD-start, respectively 1.30×/1.44×/2.12×/2.24× stronger. This effect was absent in ACPA-positive RA. In ACPA-negative RA, a strong biomarker decline is associated with early DAS remission. The combination of both declines (clinical, biomarker) was present in a subgroup of ACPA-negative RA patients achieving SDFR. This subgroup can be clinically recognized by the combination of high baseline CRP levels (≥ 3 times ULN), and early DAS remission (DAS4 months < 1.6). This latter was replicated in independent ACPA-negative RA patients.ConclusionsACPA-negative RA patients with early DAS remission and a strong biomarker response (or baseline CRP levels ≥ 3× ULN) are most likely to achieve SDFR later on. This could guide personalized decisions on DMARD tapering/cessation in ACPA-negative RA.

Formation of extracellular traps by circulating neutrophils and monocytes in rheumatoid arthritis patients: a study of new citrullinated autoantigen

Detection of subcellular structures containing typical citrullinated rheumatoid autoantigens in a single compartment presents a special interest, due to importance of anticitrulline autoantibodies for the autoimmune response in RA. Neutrophil and monocyte extracellular traps (NETs and ETs, respectively) may be considered such candidate structures. Our objective was to assess ability of blood neutrophils and monocytes from RA patients to generate NETs and ETs spontaneously and after in vitro induction.32 patients with verified RA and 30 healthy volunteers as controls were included into the study. Circulating neutrophils and monocytes were isolated with one-step density gradient centrifugation using three layers of ficoll-amidotrizoate gradient. Composition of isolated cellular fractions, their viability, and non-specific activation were evaluated microscopically using Trypan Blue exclusion test, as well as Nitro-Blue Tetrazolium test. The NETs were induced by phorbol-12-myristate-13-acetate, and ETs by bacterial LPS. Spontaneous and induced formation of extracellular traps was assessed using fluorescence microscopy. Neutrophil and monocyte fractions contained minute percentages of impurities and low extents of activated and dead cells. Spontaneous NET and ET formation in RA patients was significantly increased comparing to healthy controls. Neutrophils from ACPA-positive RA patients were found to have higher frequency of NET formation, compared to ACPA-negative RA patients. The monocytes did not demonstrate such differences between these subgroups. There were no substantial morphological differences in NETs and ETs patterns between the individuals from both groups. Induced extracellular trap production in RA was significantly higher compared to healthy controls. The level of myeloperoxidase-specific fluorescence in ETs was considerably lower than in NETs. NETs could probably be considered as a source of citrulline autoantigen participating in autoantibody production and stimulation of inflammatory autoimmune responses in RA, whereas ETs may play less important role in this process.

Early DAS response after DMARD-start increases probability of achieving sustained DMARD-free remission in rheumatoid arthritis

BackgroundSustained DMARD-free remission (SDFR) is increasingly achievable. The pathogenesis underlying SDFR development is unknown and patient characteristics at diagnosis poorly explain whether SDFR will be achieved. To increase the understanding, we studied the course of disease activity scores (DAS) over time in relation to SDFR development. Subsequently, we explored whether DAS course could be helpful identifying RA patients likely to achieve SDFR.Methods772 consecutive RA patients, promptly treated with csDMARDs (mostly methotrexate and treat-to-target treatment adjustments), were studied for SDFR development (absence of synovitis, persisting minimally 12 months after DMARD stop). The course of disease activity scores (DAS) was compared between RA patients with and without SDFR development within 7 years, using linear mixed models, stratified for ACPA. The relation between 4-month DAS and the probability of SDFR development was studied with logistic regression. Cumulative incidence of SDFR within DAS categories (< 1.6, 1.6–2.4, 2.4–3.6, ≥ 3.6) at 4 months was visualized using Kaplan-Meier curves.ResultsIn ACPA-negative RA patients, those achieving SDFR showed a remarkably stronger DAS decline within the first 4 months, compared to RA patients without SDFR; − 1.73 units (95%CI, 1.28–2.18) versus − 1.07 units (95%CI, 0.90–1.23) (p < 0.001). In APCA-positive RA patients, such an effect was not observed, yet SDFR prevalence in this group was low. In ACPA-negative RA, DAS decline in the first 4 months and absolute DAS levels at 4 months (DAS4 months) were equally predictive for SDFR development. Incidence of SDFR in ACPA-negative RA patients was high (70.2%) when DAS4 months was < 1.6, whilst SDFR was rare (7.1%) when DAS4 months was ≥ 3.6.ConclusionsIn ACPA-negative RA, an early response to treatment, i.e., a strong DAS decline within the first 4 months, is associated with a higher probability of SDFR development. DAS values at 4 months could be useful for later decisions to stop DMARDs.

ACPA-negative RA divided into clinical subsets.

ACPA-negative RA divided into clinical subsets.

Power-Doppler perfusion phenotype in RA patients is dependent on anti-citrullinated peptide antibody status, not on rheumatoid factor.

It is not known whether there are any consistent non-serological differences between seropositive and seronegative rheumatoid arthritis, and if any, whether they depend upon rheumatoid factor (RF), anti-citrullinated peptide antibodies (ACPA), or both. In a pilot study, we showed that the two forms could be differentiated using power-Doppler sonography (PDS), and that the difference is ACPA dependent. This extended study explored whether the previous findings could be confirmed. 103 patients 51 ACPA positive (ACPA +), 52 ACPA negative (ACPA -) with active wrist arthritis were examined using PDS. By means of a temporal image series, pulsatility was evaluated over a 3-5-s period, maximum and minimum perfusion signal were determined using a computer program counting the number of coloured pixels for each frame. Maxima (Pmax) and minima (Pmin) were determined, and the standardized peak-to-peak amplitude sA was calculated (sA = (Pmax - Pmin)/Pmax). This parameter was then compared for ACPA + and ACPA- patients. In addition, a multivariate regression was performed, to determine which factors influence sA. sA differed significantly between ACPA + and ACPA- patients [20% (13-26) vs. 41% (32-57), p < 0. 0001]. In the multivariate analysis, age (t = 2.5, p = 0.02) and ACPA status (t = - 4.8, p < 0.0001) were independent predictors of sA. PDS perfusion patterns are different in seropositive and seronegative RA. The difference appears to be ACPA, not RF dependent. This suggests that the underlying pathophysiological process is different in ACPA-positive and ACPA-negative RA.

Independent association of HLA-DPB1*02:01 with rheumatoid arthritis in Japanese populations.

ObjectiveRheumatoid arthritis (RA) is a chronic autoimmune disease characterized with joint destructions; environmental and genetic factors were thought to be involved in the etiology of RA. The production of anti-citrullinated peptide antibodies (ACPA) is specifically associated with RA. DRB1 is associated with the susceptibility of RA, especially ACPA-positive RA [ACPA(+)RA]. However, a few studies reported on the independent associations of DPB1 alleles with RA susceptibility. Thus, we investigated the independent association of DPB1 alleles with RA in Japanese populations.MethodsAssociation analyses of DPB1 were conducted by logistic regression analysis in 1667 RA patients and 413 controls.ResultsIn unconditioned analysis, DPB1*04:02 was nominally associated with the susceptibility of ACPA(+)RA (P = 0.0021, corrected P (Pc) = 0.0275, odds ratio [OR] 1.52, 95% confidence interval [CI] 1.16–1.99). A significant association of DPB1*02:01 with the susceptibility of ACPA(+)RA was observed, when conditioned on DRB1 (Padjusted = 0.0003, Pcadjusted = 0.0040, ORadjusted 1.47, 95%CI 1.19–1.81). DPB1*05:01 was tended to be associated with the protection against ACPA(+)RA, when conditioned on DRB1 (Padjusted = 0.0091, Pcadjusted = 0.1184, ORadjusted 0.78, 95%CI 0.65–0.94). When conditioned on DRB1, the association of DPB1*04:02 with ACPA(+)RA was disappeared. No association of DPB1 alleles with ACPA-negative RA was detected.ConclusionThe independent association of DPB1*02:01 with Japanese ACPA(+)RA was identified.

The prevalence of ACPA is lower in rheumatoid arthritis patients with an older age of onset but the composition of the ACPA response appears identical

BackgroundRheumatoid arthritis (RA) consists of two syndromes, one autoantibody-positive and one autoantibody-negative. Existing data on the relation between age of onset and prevalence of autoantibodies were conflicting. Therefore this multicohort study assessed the age of onset in relation to the presence of autoantibodies. The association with characteristics of the anti-citrullinated protein antibodies (ACPA) response was also explored.MethodsThe 1987 criteria-positive RA patients included in the Leiden EAC, BARFOT, ESPOIR, Umeå and Lund cohorts (n = 3321) were studied at presentation for age of onset and the presence of ACPA, rheumatoid factor (RF) and anti-carbamylated protein (anti-CarP) antibodies. Logistic regression analyses were performed; effect sizes were summarized in inverse-weighted meta-analyses. Within ACPA-positive RA, ACPA level was studied in all cohorts; ACPA isotypes, ACPA fine specificity and ACPA avidity index and clinical characteristics were studied in the Leiden EAC.ResultsFrom the age of 50 onward, the proportion of ACPA-negative RA patients increased with age in the five cohorts. Similar observations were made for RF and anti-CarP. The composition of the ACPA response did not change with increasing age of onset with respect to titer, isotype distribution, fine specificity and avidity index. With increasing age of onset, RA patients smoked less often, had higher acute phase reactants and more often had a sub(acute) symptom onset.ConclusionsData of five cohorts revealed that with older age of onset ACPA-negative RA is more frequent than ACPA-positive RA, while characteristics of ACPA-positive RA as judged by the composition of the ACPA response appeared not age dependent. Further biologic studies are needed to characterize the pathogenesis of ACPA-negative polyarthritis at older age and to promote personalized treatment decisions in ACPA-negative patients in daily practice.

Evidence of epistatic interaction betweenDPP4andCCR6in patients with rheumatoid arthritis

A recent genome-wide association study identified that genetic variants in DPP4 and CCR6 are connected with a risk of RA in the Han Chinese population. The aim of this study was to estimate the epistatic interaction between DPP4 and CCR6 in RA. Two single-nucleotide polymorphisms identified in a Han Chinese genome-wide association study (rs12617656 in DPP4, rs1854853 in CCR6) were genotyped. Logistic regression was used to estimate the multiplicative interaction and the additive interaction was analysed by 2 × 2 factorial design. A total of 1224 subjects (377 RA patients, 847 healthy controls) were included in the initial analysis. Additionally, 600 patients with lupus arthritis were included for comparison. Significant multiplicative interaction between DPP4 and CCR6 was observed in RA [codominant model: odds ratio (OR) = 1.49, P = 0.003]. The epistatic effect seems to be stronger in ACPA-positive RA (codominant model: OR = 1.66, P = 0.001). However, no significant multiplicative interactions were observed in ACPA-negative RA or lupus arthritis. Additive interaction analysis showed a significant epistatic effect, but only in ACPA-positive RA [attributable proportion due to interaction = 0.48 (95% CI 0.10, 0.85)]. A further replication study of an independent cohort (476 subjects) found similar results. Pooled results confirmed that there was significant interaction between DPP4 and CCR6 on both the multiplicative and additive scales. The study suggests that a genetic interaction between DPP4 and CCR6 is involved in RA susceptibility. Furthermore, these findings highlight Th17 cell response as an important contributor in the pathogenesis of RA.

An Immunochip-based interaction study of contrasting interaction effects with smoking in ACPA-positive versus ACPA-negative rheumatoid arthritis.

To investigate the gene-environment interaction between smoking and single nucleotide polymorphisms (SNPs), using Immunochip material, on the risk of developing either of two serologically defined subsets of RA. Interaction between smoking and 133,648 genetic markers from the Immunochip was examined for two RA subsets, defined by the presence or absence of ACPA. A total of 1590 ACPA-positive and 891 ACPA-negative cases were compared with 1856 controls in the Swedish Epidemiological Investigation of RA (EIRA) case-control study. Logistic regression models were used to determine the presence of interaction. The proportion attributable to interaction was calculated for each smoking-SNP pair. Replication was carried out in an independent dataset from northern Sweden. To further validate and extend the results, interaction analysis was also performed using genome-wide association studies data on EIRA individuals. In ACPA-positive RA, 102 SNPs interacted significantly with smoking, after Bonferroni correction. All 102 SNPs were located in the HLA region, mainly within the HLA class II region, 51 of which were replicated. No additional loci outside chromosome 6 were identified in the genome-wide association studies validation. After adjusting for HLA-DRB1 shared epitope, 15 smoking-SNP pairs remained significant for ACPA-positive RA, with 8 of these replicated (loci: BTNL2, HLA-DRA, HLA-DRB5, HLA-DQA1, HLA-DOB and TAP2). For ACPA-negative RA, no smoking-SNP pairs passed the threshold for significance. Our study presents extended gene variation patterns involved in gene-smoking interaction in ACPA-positive, but not ACPA-negative, RA. Notably, variants in HLA-DRB1 and those in additional genes within the MHC class II region, but not in any other gene regions, showed interaction with smoking.

Genetic Factors for the Severity of ACPA-negative Rheumatoid Arthritis in 2 Cohorts of Early Disease: A Genome-wide Study.

Rheumatoid arthritis (RA) that is negative for anticitrullinated protein antibodies (ACPA) is a subentity of RA, characterized by less severe disease. At the individual level, however, considerable differences in the severity of joint destruction occur. We performed a study on genetic factors underlying the differences in joint destruction in ACPA-negative patients. A genome-wide association study was done with 262 ACPA-negative patients with early RA included in the Leiden Early Arthritis Clinic and related to radiographic joint destruction over 7 years. Significant single-nucleotide polymorphisms (SNP) were evaluated for association with progression of radiographic joint destruction in 253 ACPA-negative patients with early RA included in the Better Anti-Rheumatic Farmaco Therapy (BARFOT) study. According to the Bonferroni correction of the number of tested SNP, the threshold for significance was p < 2 × 10(-7) in phase 1 and 0.0045 in phase 2. In both cohorts, joint destruction was measured by Sharp/van der Heijde method with good reproducibility. Thirty-three SNP associated with severity of joint destruction (p < 2 × 10(-7)) in phase 1. In phase 2, rs2833522 (p = 0.0049) showed borderline significance. A combined analysis of both the Leiden and BARFOT datasets of rs2833522 confirmed this association with joint destruction (p = 3.57 × 10(-9)); the minor allele (A) associated with more severe damage (for instance, after 7 yrs followup, patients carrying AA had 1.22 times more joint damage compared to patients carrying AG and 1.50 times more joint damage than patients carrying GG). In silico analysis using the ENCODE and Ensembl databases showed presence of H3K4me3 histone mark, transcription factors, and long noncoding RNA in the region of rs2833522, an intergenic SNP located between HUNK and SCAF4. Rs2833522 might be associated with the severity of joint destruction in ACPA-negative RA.

SAT0200 Clinical Application of the Soluble Lectin-Like Oxidized LDL Receptor-1 (SLOX-1) in Rheumatoid Arthritis: from Bench to Bedside

BackgroundPreviously, we have reported that levels of sLOX-1 (soluble Lectin-like oxidized LDL receptor 1) in the plasma of RA patients were significantly higher than those in healthy controls, and the...

FRI0368 To Which Extent May the Familial Risk of Rheumatoid Arthritis BE Explained by Established Risk Factors?

BackgroundRheumatoid arthritis (RA) is a complex inflammatory disease known to aggregate within families, implicating the crucial role of shared genetic and/or environmental factors in its etiology. Despite the many advances...

OP0035 When Does the Therapeutic Window of Opportunity in Rheumatoid Arthritis Close? A Study in Two Early RA Cohorts

BackgroundObservational cohort studies and clinical trials have shown that early initiation of DMARD-therapy is associated with less disease persistency (a higher frequency of DMARD-free sustained remission).1 It has been suggested...

97. Final 5-Year Safety and Efficacy Results of a Phase 3, Randomized, Placebo-Controlled Trial of Golimumab in Methotrexate-NaïVe Patients with Rheumatoid Arthritis

randomized controlled trial (RCT)—the Combination Anti-Rheumatic Drugs in Early RA (CARDERA) trial—to examine whether responses to intensive combination treatments in early RA differ by ACPA status. Methods: The CARDERA trial randomized 467 patients with early active RA to receive: (i) MTX (ii) MTX/ciclosporin (iii) MTX/prednisolone or (4) MTX/ciclosporin/prednisolone in a factorial-design. Patients were assessed 6 monthly for 2 years. In this analysis we evaluated 431 patients with archived serum available for ACPA status determination (using the anti-CCP2 ELISA assay). To minimize multiple testing we used a mixed-effects repeated measures ANOVA model to test for an interaction between ACPA and treatment on mean changes from baseline for each outcome (Larsen, DAS28, HAQ, EuroQol, PCS and MCS scores). When a significant interaction was present, mean changes in outcomes were compared by treatment group at each time point stratified by ACPA status using t-tests. Odds ratios (ORs) for the onset of new erosions with treatment were calculated stratified by ACPA. Results: Of the 431 RA cases, 310 (72%) were ACPA-positive; 121 (28%) were ACPA-negative. ACPA status influenced the effect of treatment on radiological progression, with a significant ACPA*treatment interactive effect on Larsen score changes seen in the ANOVA model (P< 0.001). ACPA-positive patients had significant reductions in Larsen score progression with all treatments; no effect was seen in ACPAnegative RA. ACPA-positive patients receiving triple therapy had the greatest benefits: mean Larsen score increases over 2 years were 3.66 (95% CI 2.27, 5.05) with triple therapy and 9.58 (95% CI 6.76, 12.39) with monotherapy; OR for new erosions with triple therapy vs monotherapy was 0.32 (95% CI 0.14, 0.72; P1⁄40.003). ACPA-negative patients had minimal radiological progression irrespective of treatment strategy: mean Larsen score increases over 2 years comprised 1.70 (95% CI 0.29, 3.10) with triple therapy and 2.72 (95% CI 1.15, 4.29) with monotherapy; only 7% developed new erosions. The beneficial effects of high-dose corticosteroids on reducing disease activity and improving physical health were confined to ACPA-positive RA. Conclusion: ACPA status influences the need for, and response to, combination DMARDs and high-dose tapering corticosteroids in early RA. Combination DMARDs and corticosteroids only provided radiological, disease activity and physical health benefits in ACPA-positive patients. This suggests that current UK guidelines advocating combination DMARDs and corticosteroids in all early active RA patients require reconsideration. Funding: This research was supported Arthritis Research UK [Grant Number 19739 to ICS], the National Institute for Health Research (NIHR) and the NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust in partnership with King’s College London. Disclosure statement: The authors have declared no conflicts of interest.