anti-CCP Autoantibodies Research Articles

Haptoglobin 2-2 genotype is associated with increased risk of cardiovascular disease in patients with rheumatoid arthritis: a matched case-control study

IntroductionTraditional risk factors do not fully explain the increased risk of cardiovascular disease (CVD) in patients with rheumatoid arthritis (RA). The Haptoglobin (Hp) 2-2 genotype confers a lower anti-oxidant and higher inflammatory effect on the vasculature compared to the non-Hp 2-2 genotype. This study investigates the association of the Hp genotype with CVD in patients with RA.MethodsData from 69 RA patients with CVD and 207 sex- and ethnicity-matched RA patients without CVD, collected from 1 January 2000 to 31 December 2020, were retrieved from the Tan Tock Seng Hospital RA Registry. CVD was examined against demographics, clinical and laboratory variables in univariate models. Associations between the Hp genotypes and CVD were analyzed using conditional logistic regression.ResultsWe studied 276 patients (65.2% female, 82.6% Chinese, median age 60.9 years). Most participants were in low disease activity or remission (79.3%). The Hp 2-2 genotype was present in 49.6% (137/276). In the group with CVD, the prevalence of the Hp 2-2 genotype was 50.9% (29/57) in the Chinese, 100% (5/5) in the Indians, and 28.6% (2/7) in the Malays. In the non-CVD group, the respective prevalence was 46.8% (80/171), 66.7% (10/15), and 52.4% (11/21). In univariate analysis, the matched odds ratio (OR) of the Hp 2-2 genotype for CVD in RA was 1.34 [95% confidence interval (CI): 1.22–1.47; p < 0.001]. The Hp 2-2 genotype was significantly associated with CVD (adjusted matched OR: 1.13; 95% CI: 1.01–1.27; p = 0.033) in the multivariate logistic regression model after adjusting the confounding factors, including age, smoking, diabetes, hypertension, hyperlipidemia, anti-CCP autoantibodies, and disease activity.ConclusionThe Hp 2-2 genotype is associated with an increased risk of CVD in patients with RA in this multi-ethnic cohort.

Endogenous retroelement activation is implicated in IFN-α production and anti-CCP autoantibody generation in early Rheumatoid Arthritis.

Endogenous retroelements (EREs) stimulate type 1 interferon (IFN-I) production but have not been explored as potential interferonogenic triggers in Rheumatoid Arthritis (RA). We investigated ERE expression in early RA (eRA), a period where IFN-I is increased. ERE expression (LTR5, LINE1, SINE) in disease modifying treatment naïve eRA whole blood and bulk synovial tissue was examined by RT-PCR and Nanostring alongside IFN-α activity. Circulating lymphocyte subsets, including B cell subsets, from eRA patients and early psoriatic arthritis (ePsA), were flow cytometrically sorted and similarly examined. Existing established RA and osteoarthritis (OA) synovial single-cell sequencing data was re-interrogated to identify repeat elements, and associations explored. There was significant co-expression of all ERE classes and IFNA in eRA synovial tissue (n=22, p<0.0001) and significant positive associations between whole blood LINE1 expression (n=56) and circulating IFN-α protein (p=0.018) and anti-CCP titres (p<0.0001). ERE expression was highest in circulating eRA B-cells, particularly naïve B-cells compared with ePsA, with possible ERE regulation by SAMDH1 implicated and associations with IFNA again observed. Finally, in established RA synovium, LTRs, particularly ERVK, were most increased in RA compared with OA where, for all synovial subsets (monocytes, B-cells, T-cells and fibroblasts), ERE expression associated with increased IFN-I signalling (p<0.001). Peripheral blood and synovial ERE expression is examined for the first time in eRA highlighting both a potential causal relationship between ERE and IFN-I production and an intriguing association with anti-CCP autoantibodies. This suggests EREs may contribute to RA pathophysiology with implications for future novel therapeutic strategies.

Rheumatoid arthritis patients harbour aberrant enteric bacteriophages with autoimmunity-provoking potential: a paired sibling study

ObjectivesViruses have been considered as important participants in the development of rheumatoid arthritis (RA). However, the profile of enteric virome and its role in RA remains elusive. This study aimed...

Double positivity for rheumatoid factor and anti-CCP autoantibodies: improving referral from primary care of patients suspected of having rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic progressive autoimmune inflammatory disease with significant morbidity and mortality. The course of the disease can be modified if diagnosis is early and treatment appropriate. In this study, we aimed to evaluate a new strategy for early identification of RA patients in primary care settings (the 'diagnostic bottleneck') based on serological biomarkers and to manage inappropriate rheumatoid factor (RF) laboratory test requests. A two-arm study was carried out. The first arm corresponded to a retrospective observational descriptive study of patients referred for RF testing from primary care using the current laboratory workflow. The second arm included the following prospective interventions: cancelation of RF requests corresponding to patients with previous negative results for RF over a one-year period; and automatic reflex testing antibodies against cyclic citrullinated proteins (anti-CCP) for patients displaying RF values >30IU/ml. Outcomes from both arms were then compared. As double positivity for RF and anti-CCP notably increases the positive likelihood ratio of RA. The intervention enabled a reduction of 2813 tests in 22 months. Moreover, the frequency of unnecessary referrals was reduced from 22% to 8.2%, while that of missed patients decreased slightly (from 21% to 16%), with the number of patients diagnosed per RF request remaining unchanged. In terms of costs, we saved 19.4 RF tests per anti-CCP test added.We developed a simple and cost-effective strategy for reducing the time to diagnosis of RA that can improve patients' quality of life. This approach was supported by primary and specialised care.

Porphyromonas Gingivalis - A Periodontal Pathogen with Potential Role in Rheumatoid Arthritis and its Association with Anti-CCP and Anti-MCV Antibodies Positivity

Background: In recent studies, a strong association between rheumatoid arthritis (RA) and chronic periodontal disease (CPD) has been identified, indicating common disease pathogenesis and risk factors. One of them is the presence of the pathogen Porphyromonas gingivalis (PG), which can initiate the process of citrullination, by secreting the enzyme Porphyromonas Peptydil Arginine Deminase (PPAD).&#x0D; The aim of the study is to show the presence of PG in RA patients, and to evaluate the association of the PG presence with anti-citrullinated proteins/peptides (ACPA) positivity i.e. anti CCP and anti MCV positivity.&#x0D; Methods: The study included 80 participants - 30 patients which fulfilled 2010 ACR/EULAR RA classification criteria and 50 controls, which were genetically analyzed for the presence of PG by Chelex®100 method and polymerase chain reaction (PCR) and for the presence of anti CCP and anti MCV autoantibodies with the ELISA method.&#x0D; Results: Twenty out of thirty RA patients (80 %) and 16 out of 50 controls (32%) were positive for PG. (χ 2 = 11.461, p &lt;0.001 for OA and χ2 = 13.91, p &lt;0.001 for HC). Of the PG-positive RA patients, 83% had positive anti-CCP and 79% had positive anti-MCV test. The odds ratios OR of 25 and 19 were statistically significant (p = 0.008 and p =0,014 respectfully).&#x0D; Conclusions: PG was present more frequently in RA patients and there was a statistically significant association with anti CCP and anti MCV antibodies.

Peptide-based electrochemical sensor with nanogold enhancement for detecting rheumatoid arthritis

Rheumatoid arthritis (RA), an autoimmune and chronic inflammatory disorder, is an incurable disease. We developed a peptide-based electrochemical sensor using electrochemical impedance spectroscopy that can be used to detect autoantibodies for RA diagnostics. We first validated that the developed peptide showed high sensitivity and could compliment the current gold standard method of an anti-cyclic citrullinated peptide antibody (anti-CCP) ELISA. The developed peptide can be modified on the nanogold surface of the working electrode of sensing chips through the method of a self-assembling monolayer. The sensing process was first optimized using a positive control cohort and a healthy control cohort. Subsequently, 10 clinically confirmed samples from RA patients and five healthy control samples were used to find the threshold value of the impedance between RA and healthy subjects. Furthermore, 10 clinically confirmed samples but with low values of anti-CCP autoantibodies were used to evaluate the sensitivity of the present method compared to the conventional method. The proposed method showed better sensitivity than the current conventional anti-CCP ELISA method.

Unique autoantibody prevalence in long-term recovered SARS-CoV-2-infected individuals

The variability in resolution of SARS-CoV-2-infections between individuals neither is comprehended, nor are the long-term immunological consequences. To assess the long-term impact of a SARS-CoV-2-infection on the immune system, we conducted a prospective study of 80 acute and former SARS-CoV-2 infected individuals and 39 unexposed donors to evaluate autoantibody responses and immune composition. Autoantibody levels against cyclic citrullinated peptide (CCP), a specific predictor for rheumatoid arthritis (RA), were significantly (p = 0.035) elevated in convalescents only, whereas both acute COVID-19 patients and long-term convalescents showed critically increased levels of anti-tissue transglutaminase (TG), a specific predictor of celiac disease (CD) (p = 0.002). Both, anti-CCP and anti-TG antibody levels were still detectable after 4–8 months post infection. Anti-TG antibodies occurred predominantly in aged patients in a context of a post-SARS-CoV-2-specific immune composition (R2 = 0.31; p = 0.044). This study shows that increased anti-CCP and anti-TG autoantibody levels can remain long-term after recovering even from mildly experienced COVID-19. The inter-relationship of the lung as viral entry side and RA- and CD-associated autoimmunity indicates that a SARS-CoV-2-infection could be a relevant environmental factor in their pathogenesis.

AB0155 COMPARATIVE ANALYSES OF SEROLOGICAL BIOMARKERS AND DISEASE CHARACTERISTICS BETWEEN ELDERLY ONSET RHEUMATOID ARTHRITIS (EORA) AND YOUNGER ONSET RHEUMATOID ARTHRITIS (YORA)

Background:Several studies have reported differences in disease characteristics between elderly onset RA (EORA: age of onset &gt; 60 years) and younger-onset RA (YORA). However, the findings across the studies have been rather inconsistent owing partially to the genetic variation across the populations studied. While a few studies have looked into the clinical aspects of EORA, there is a profound lack of comparative data on serological findings between EORA and YORA. Seropositive RA is known to be associated with more aggressive disease and the titres of the autoantibodies may predict the disease activity and the severity of radiographic progression.Objectives:The main aim of this study was to compare the levels of the autoantibodies namely anti–CCP (cyclic citrulinated peptide), IgA, IgM, IgG rheumatoid factors(RF) and disease characteristics between the EORA and YORA groups.Methods:We consecutively recruited a total of 151 female RA patients who were tested for IgA RF, IgG RF, IgM RF and anti CCP antibodies. Participants were aged above 18 years and met the 2010 ACR/EULAR RA criteria. Data on the disease characteristics (age at onset, disease activity at onset, disease duration and medications)were obtained by reviewing the medical records of the subjects. Subjects were divided into 2 groups i.e EORA and YORA based on age at onset of RA. All subjects were assessed for the severity of radiographic joint damage and functional disability based on Modified Sharp Score (MSS) and Health-assessment questionnaire-disability index (HAQ- DI), respectively. The EULAR response criteria was used to determine the subjects’ response to disease-modifying anti-rheumatic drugs.Results:The EORA group had 69 patients whereas the YORA group had 82 patients. The mean anti-CCP and IgA RF levels were significantly higher in the YORA group with p values of 0.002 and 0.035, respectively. The YORA group had significantly more severe disease at onset (p value for DAS 28 at onset was 0.009) with worse radiographic joint damage (p value for MSS was 0.006). In parallel with these findings, the YORA group had significantly higher ESR and CRP at onset with higher frequency of subjects requiring advanced therapies. The differences in frequency of RF positivity, disease duration, number of DMARDs, prednisolone dose and HAQ-Di scores between the groups did not reach statistical significance.Conclusion:EORA is characterized by lower levels of anti-CCP and IgA autoantibodies with less aggressive disease as compared to YORA.

Significance of Hyaluronic acid as a biomarker with seropositive and seronegative autoantibodies in Rheumatoid arthritis patients

Testing for autoantibodies is a flagship feature of Rheumatoid arthritis (RA), a chronic inflammatory autoimmune disorder affecting both the male and female population. Synovial inflammation followed by cartilage, bone, and joint destruction in the later stages of RA puts life in peril, especially for those with other comorbidities. In this study, we focused on to measure serum Hyaluronic acid (HA) along with seropositive and seronegative RF, AntiCCP autoantibodies to establish any association with these biomarkers. It was a cross-sectional study involving 152 RA patients based on the 1987 ACR criteria for the diagnosis of RA and 68 age‑ and sex-matched healthy controls. After clinical examination, the traditional markers were assessed to measure the disease activity, such as CRP, ESR, Anti -CCP, and RF in RA patients. The serum HA levels were measured using the ELISA method. All the values were expressed as median (25th–75th percentile). Based on seropositive and seronegative RF and AntiCCP autoantibodies, the patient group was divided into four groups- both seropositive, both seronegative, and the other two mixed groups. The traditional inflammatory markers were significantly increased in RA patients than in controls with (p &lt; 0.001). In our study, there was a significant increase in serum HA levels in RA patients compared to healthy controls (p &lt; 0.03). The serum HA levels were significantly correlated with Anti-CCP, DAS‑28, CRP, and ESR in RA patients. At the same time, serum HA level is increased in the group with seropositive for both antibodies showing statistical significance. Conclusion- serum Hyaluronic acid is involved in synovial inflammation, manifesting a common triggering mechanism more with AntiCCP antibodies than RF, promising for better clinical utility in the early stages of rheumatoid arthritis.

Improved classification of rheumatoid arthritis with a score including anti-acetylated ornithine antibodies

The presence of rheumatoid factor (RF) or anti-cyclic citrullinated peptide (anti-CCP) autoantibodies contributes to the current rheumatoid arthritis (RA) classification criteria. These criteria involve stratification on antibody levels, which limits reproducibility, and underperform in the RA patients without RF and anti-CCP. Here, we have explored if two anti-acetylated peptide antibodies (AAPA), anti-acetylated lysine (AcLys) and anti-acetylated ornithine (AcOrn), could improve the performance of the current criteria. The analysis was done in 1062 prospectively-followed early arthritis (EA) patients. The anti-AcOrn were more informative than the anti-AcLys, the conventional RA antibodies and the anti-carbamylated protein antibodies. The anti-AcOrn produced a classification that did not require antibody levels and showed improved specificity (77.6% vs. 72.6%, p = 0.003) and accuracy (79.0% vs. 75.8%, p = 0.002) over the current criteria. These improvements were obtained with a scoring system that values concordance between anti-AcOrn, RF and anti-CCP. No significant gain was obtained in sensitivity (80.2% vs. 78.8%, p = 0.25) or in improving the classification of the RA patients lacking RF and anti-CCP, although the anti-AcOrn ranked first among the analysed new antibodies. Therefore, the anti-AcOrn antibodies could contribute to the improvement of RA classification criteria by exploiting antibody concordance.

FRI0565 PREVALENCE AND SIGNIFICANCE OF ANTIBODIES AGAINST CITRULLINATED ALPHA-ENOLASE (ANTI-CEP1) IN CONNECTIVE TISSUE DISEASES.

Background:Anti-cyclic citrullinated peptide (anti-CCP) auto-antibodies represent the current gold standard for the diagnosis of rheumatoid arthritis (RA). However, growing evidence suggests that a variety of other citrullinated self-proteins may act as autoantigens and lead to the production of autoantibodies (1). Furthermore, autoantibodies believed to be RA-specific have been detected also in patients with connective tissue diseases (CTDs). We recently demonstrated that antibodies against citrullinated alpha-enolase (anti-CEP1) are a biomarker of erosive disease and RA-associated interstitial lung disease (2).Objectives:The purpose of this study was to investigate the prevalence and possible prognostic value of anti-CEP-1 in patients with CTDs.Methods:Two hundred and twelve consecutive patients with CTDs (51 systemic lupus erythematosus (SLE), 85 primary Sjogren’s syndrome (pSS) and 76 systemic sclerosis (SSc)) were studied and compared to 97 sex and age matched normal controls (NC) and 267 patients with RA. Anti-CEP1 IgG were detected in serum samples with a commercial ELISA kit (Euroimmun).Results:The overall prevalence of anti-CEP1 in CTDs was 7% (15/212 patients). In detail, these antibodies were detectable in 4 out of 85 pSS (5%), 5 out of 51 SLE (10%) and 6/76 SSc (8%). The prevalence and the titer of anti-CEP1 in CTDs was significantly higher compared to NC and significantly lower compared to RA. Anti-CEP1 positive patients did not display a specific clinical and serological picture. Unlike in RA, anti-CEP1 did not correlate with CTD-associated ILD.Conclusion:This is the first study assessing anti-CEP1 in a large cohort of patients with CTDs. We demonstrated that the association of these autoantibodies with ILD is specific for RA since it is not observed in SLE, pSS and SSc. Furthermore, although being significantly more prevalent and at higher titer compared to NC, anti-CEP1 do not allow to discriminate different patient subsets displaying peculiar clinical or serological phenotypes. Based on our results, the application of anti-CEP1 in CTDs is not advisable, however larger studies may possibly identify correlations not evident in our cohort.

Evaluation of clinical and Para clinical findings and treatment response in RA patients: Data from a single center RA registry

Background and objectiveRheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease characterized by inflammatory arthritis, rheumatoid factor (RF) and anti-cyclic citrullinated peptide (Anti-CCP) autoantibodies. In the present study, the aim was to register RA patients in Tehran Imam Khomeini Hospital.Methods and materialThe study population was RA patients referred to the rheumatology clinic of Imam Khomeini Hospital in Tehran, who were visited at this clinic in 1398 and were diagnosed during the 5 years ago. Demographic, clinical, and laboratory information of patients at the beginning of referral, 3 months, 1, 2, 3, and 4 years after referral were carefully recorded in each patients’ questionnaire.ResultsIn the first visit, 79 RA patients were examined and in the other 5 visits, 73, 52, 33, 20, 13 patients and all of 270 visits were examined, respectively. RF and Anti-CCP were positive in 58.22% and 62.02% of patients, respectively.The mean age of patients was 52.5±11.25 years. The results of the present study showed that the mean morning stiffness, DAS, arthritis, arthralgia, ESR and CRP decreased from the second visit to the five visits, which indicates disease control.ConclusionClinical and laboratory data showed considarable disease control, however, relapse of disease was seen due to drug discontinuation. Disease registry make it possible to recording the necessary information of each patient, including demographic, clinical, paraclinical findings and consultations, also gives the physician accurate access to patient information and unnecessary duplication of paraclinical examinations.

Detection of Some Genetic Polymorphism and Serological Factors Associated with Rheumatoid Arthritis in Egyptian Patients

Background: Rheumatoid arthritis is a chronic inflammatory autoimmune disease thatis characterized by destruction of cartilage and bone. PADI4 gene encoding the peptidyl arginine deiminase 4 citrullinating enzyme that has been found to be over expressed in rheumatoid arthritis patients. Objective: To investigate relation between PADI4 gene polymorphisms and anti–cyclic citrullinated peptide (Anti-CCP) autoantibody levels in sera of Egyptian rheumatoid arthritis patients, and to find its relevance to the disease activity(DAS28 score) and other inflammatory markers as Rheumatoid factor (RF). Methods: PADI4-89 andPADI4 -92 single nucleotide polymorphisms (SNPs) were analyzed in thirty RA patients and twenty healthy controls by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method. Serum anti-CCP levels were measured by enzyme-linked immunosorbent assay (ELISA). Results: PADI4-89 genotype A/G was present in RA patients at higher frequency compared to controls (P = 0.024). (G) allele frequency was significantly higher in RA patients than in controls (P= 0.047). Level of Anti – CCP was significantly higher in RA patients serum than in controls (P= 0.000).PADI4-89 A/G + G/G genotype and PADI4-92 C/G+GG genotype were associated with higher DAS28 score, Rheumatoid factor (RF), and anti-cyclic citrullinated protein (Anti – CCP). Significant positive correlation was found between serum level of Anti– CCP and DAS28 score (P= 0.023). Conclusion: The SNPs A/G and G/G of PADI4-89 were associated with RA susceptibility. Relation was found between both PADI4 polymorphism and anti-CCP levels.

Role of HLA-DRB1, PTPN22, CTLA4 Gene Polymorphisms in Susceptibility to Rheumatoid Arthritis

Background and AIM: The genetic and environmental factors are believed to play an important role in the pathogenesis of rheumatoid arthritis (RA), the precise etiology is still uncertain. Regarding its genetic components, the strongest genetic association with RA is that found for certain alleles of HLA-DRB1. Recent studies have revealed that the single‐nucleotide polymorphism (SNP) of non-HLA PTPN22 and CTLA4 gene were associated with RA. The associations of HLA, PTPN22 and CTLA4 polymorphisms with RA risk have been less well replicated. Thus, the current study was undertaken to investigate the effects of HLA-DRB1, PTPN22, CTLA4 gene polymorphisms and autoantibodies in susceptibility to RA. Methods: A total of 200 patients fulfilled the criteria for RA and 200 healthy individuals were included in the study. Anti-cyclic citrullinated peptide (anti-CCP) antibodies and rheumatoid factor (RF) were measured by enzyme-linked immunosorbent assay (ELISA). HLA-DRB1 alleles were determined by polymerase chain reaction-sequence specific primer (PCR-SSP) method. Samples were genotyped for PTPN22 1858C/T (rs2476601) and CTLA4 CT60 (rs3087243) variants using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results: In RA patients 88% and 82% were positive for anti-CCP and RF autoantibodies, respectively. A significant increase in the frequency of HLA-DRB1*01, HLA-DRB1*04, HLA-DRB1*10, HLA-DRB1*14 shared epitope (SE) alleles were identified in RA patients, whereas in healthy subjects, they were HLADRB1*03, HLA-DRB1*07, HLA-DRB1*11, HLA-DRB1*13. There was no association of the PTPN22 1858T variant with RA and it seems to be independent of MHC associations. The frequency of CTLA4 CT60 A allele carriers was significantly higher in RA patients and also it is preferentially in SE-positive RA patients. Conclusion: Our results confirmed the previously reported HLA-DRB1 SE alleles associations with RA. The CTLA4 polymorphism appears to interfere with HLA-DRB1 susceptibility to RA. On the other hand, we failed to provide evidence for the association of the PTPN22 SNP with RA.

Effects of environmental factors and omega-3 fatty acids on rheumatoid arthritis

With a prevalence that has been estimated to be 0.5%±0.2% and a female predominance, rheumatoid arthritis (RA) represents the most common chronic systemic autoimmune rheumatism. Typically, RA is characterized by polyarticular pain, morning stiffness, fatigue, joint and bone inflammation and destruction (1). A more severe evolution is encountered in RA patients with an age lower than 50 years at diagnosis, anti-cyclic citrullinated peptides (anti-CCP) autoantibody (Ab) positivity, IgM rheumatoid factor (RF) at elevated levels (>50 UI/mL), and bone erosions (2,3). RA appears to present geographical variations with an apparent reduction from north to the south, and from urban to rural areas (4).

Study of Peptidyl Arginine Deiminases 4 (PAD 4) Antibodies in Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA) is one of the most commonly occurring form of inflammatory polyarthritis. If untreated,20%–30% of RA patients become debilitated within the first three years following initial diagnosis. The clinical examinationoften fail to identify patients with early RA partly due to heterogeneity of disease presentation and course. To meet the needfor improved diagnostic and prognostic tests, various serum biomarkers are being assessed, including a wide range ofautoantibodies. Autoantibodies against peptidyl arginine deiminase type 4 (PAD-4) have recently been described as a specificbiomarker in subjects with clinically apparent RA. In this study, we tested the presence of anti-PAD4 antibodies in 40Egyptian subjects with RA and their first degree relatives in order to determine whether these autoantibodies play a role inearly disease evolution. In addition, we aimed to describe the Anti-PAD4 relation to anti-CCP autoantibodies, and potentialassociations with a more severe RA phenotype. The study was carried out on total of 100 subjects divided into; 40 RApatients, 40 of first degree relatives (sister or brother) of RA patients and 20 matched controls. Results: The resultsindicated that the serum level of Anti-PAD 4 is increased in Egyptian RA patients and their relatives and has a positiveassociation with disease activity. Also its level together with Anti-CCP provides a good diagnostic tool of RA. Conclusion:The serum level of Anti-PAD4 may provide diagnostic information of RA and may be considered as an early marker of thedisease among the first degree relatives of RA patients. [Egypt J Rheumatology & Clinical Immunology, 2016; 4(1): 59-66]

Lower omega-3 fatty acids are associated with the presence of anti-cyclic citrullinated peptide autoantibodies in a population at risk for future rheumatoid arthritis: a nested case-control study.

The aim of this study was to investigate omega-3 fatty acid (FA) supplement use and omega-3 FAs in erythrocyte membranes [omega-3 FA % in erythrocyte membranes (RBC)] and their association with anti-CCP autoantibodies in a population without RA, but who are at genetic risk for RA. The multicentre Studies of the Etiology of RA (SERA) cohort includes RA-free subjects who are first-degree relatives of RA probands or are enriched with the HLA-DR4 allele. In a nested case-control study, 30 SERA cases were identified who were anti-CCP2 antibody positive. We further identified 47 autoantibody negative controls, frequency matched to cases on age at study visit, sex, race and study site. Anti-CCP2 status, self-reported omega-3 FA supplement use and omega-3 FA % in RBCs were obtained from a single visit. Anti-CCP2 positive cases were less likely than controls to report omega-3 FA supplement use (odds ratio: 0.14; 95% CI 0.03, 0.68). In addition, the likelihood of anti-CCP2 positivity was inversely associated with total omega-3 FA % in RBCs (odds ratio: 0.47; 95% CI 0.24, 0.92, for a s.d. increase). The inverse association between anti-CCP2 positivity and self-reported omega-3 FA supplement use and omega-3 FA % in RBCs suggests that omega-3 FAs may protect against the development of RA-related autoimmunity in pre-clinical RA.

Enhanced neutrophil phagocytic capacity in rheumatoid arthritis related to the autoantibodies rheumatoid factor and anti-cyclic citrullinated peptides.

BackgroundThere is no consensus on the mechanisms by which anti-cyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factor (RF) influence the pathogenesis of rheumatoid arthritis (RA). The current study verified if the presence of RF or anti-CCP is associated with phagocytic capacity and reactive oxygen species (ROS) production by phagocytes in RA patients to better clarify the role played by these antibodies in pathogenesis of the disease.MethodsA cohort of 30 RA patients followed from early stages of the disease were characterized by positivity for RF or anti-CCP, disease activity score (DAS-28), health assessment questionnaire (HAQ), use of synthetic or biologic therapy, lifestyle, comorbidities and radiographic erosions. Phagocytic capacity against Saccharomyces cerevisiae and superoxide anion production were assessed in RA patients and compared with 20 healthy controls. Phagocytic capacity and superoxide anion production were also compared between RF- and anti-CCP-positive and -negative RA patients.ResultsAnti-CCP- and RF-positive RA patients had higher neutrophil phagocytic capacity than anti-CCP- (p = 0.005) and RF (p = 0.005)-negative individuals through pattern-recognition receptors. As assessed via pattern recognition or opsonin receptors, neutrophils and monocytes from RA patients presented overall higher phagocytic capacity than neutrophils and monocytes from healthy controls (p < 0.05). Furthermore, RA patients also showed a higher capacity for producing cytotoxic oxygen radicals (p = 0.0026). Phagocytosis and superoxide anion production did not correlate with any of the clinical variables analyzed in this study.ConclusionsThis study showed increased phagocytosis by neutrophils in RA patients who were positive for anti-CCP and RF autoantibodies. Furthermore, there was an overall hyperactivation of the phagocytes in RA patients. Our data suggest that anti-CCP and RF may indirectly enhance the inflammation cascade involving neutrophils and may indirectly sustain tissue damage in RA. Targeting the production of these autoantibodies may be a promising strategy in the management of RA.

Can tocilizumab decrease cartilage oligomeric matrix protein levels and disease activity in patients with long-standing rheumatoid arthritis?

Serum cartilage oligomeric matrix protein (COMP) level is a new marker of joint destruction in patients with rheumatoid arthritis (RA), and a new means of identifying patients with progressive joint damage. To evaluate the effect of tocilizumab (TCZ) on serum COMP levels, and whether there is any difference in this effect between patients failing on anti-TNF treatment and those failing on disease-modifying anti-rheumatic drugs (DMARDs). Fifty-one patients with long-standing RA (42 F, 9 M; mean age 62 ± 14 years; disease duration 4.5 ± 1.2 years) unresponsive to DMARDs and anti-TNF drugs were treated with TCZ 8 mg/kg/month. Serum COMP levels were measured by means of an ELISA at baseline and after six months of TCZ treatment; the patents' DAS28 scores and levels of RF (IgM, IgG, IgA), anti-CCP autoantibodies, ESR, CRP and IL-6 were evaluated at the same times. After six months of TCZ treatment, there was a significant decrease from baseline in ESR (46.1 [28.7-68.9] vs 34.3 [4.1- 58.8] mm/h, P <0.0001), CRP (2.2 [0.8-4.4] vs 1.3 [0.7-3.8] mg/dL, P <0.0001), TNF-α (21.3 [7.6-29.8] vs 17.4 [3.4-28.6] pg/mL, P=0.0408), IL-6 (6.9 [3.5-9.6] vs 3.4 [3.0-9.6] pg/mL, p<0.0001); anti-CCP (55.1 [30.2-273.0] vs 54.7 [30.1- 269.8] IU/mL, P=0.9683), RF-IgM (142.0 [48.0-260.0] vs 138.0 [42.0-243.0] IU/mL, P=0.4828), RF-IgA (81.0 [20-140] vs 108.0 [20-175] U/mL, P=0.0003), and RF-IgG (65.2 [30-158] vs 58.3 [38.0-158.0] U/mL, P=0.2671). There was also a significant decrease in DAS28 scores (4.3 [3.2-5.9] vs 3.7 [2.3-5.4], P <0.0001), and a non-significant decrease in serum COMP levels (0.95 [0.04-2.90] vs 0.98 [0.05-2.36] μg/mL; P = 0.9856). A decrease in serum COMP levels was observed in the patients failing on anti-TNF treatment or anti-DMARDs without any difference. TCZ therapy in patients with long-standing RA is associated with a significant decrease in ESR, CRP, IL-6, TNF and DAS28 values, and a decrease in serum COMP levels, particularly in patients failing on previous anti-TNF therapy. These findings suggest that TCZ has an effect on cartilage joint destruction after only six months of treatment.

Expression of the Inherently Autoreactive Idiotope 9G4 on Autoantibodies to Citrullinated Peptides and on Rheumatoid Factors in Patients with Early and Established Rheumatoid Arthritis

BackgroundThe pre-symptomatic stage of Rheumatoid arthritis (RA) is associated with pro-inflammatory cytokines and autoantibodies. High levels and epitope spread by Rheumatoid factors (RhF) and autoantibodies to citrullinated proteins signify progression towards disease expression. In established RA, the persistence of high autoantibody levels reflects production by both long-lived plasma cells and short-lived plasmablasts. Neither the relative contributions to pathogenesis by autoantibodies from either source, nor the factors responsible for deciding the fate of autoantigen specific ‘parent’ B-cells, is understood. Phenotypic markers identifying subsets of autoreactive B-cells are therefore of interest in understanding the origin and perpetuation of the autoimmune response in RA. One such phenotypic marker is the rat monoclonal antibody, 9G4, which recognises an idiotope on immunoglobuins derived from the inherently autoreactive VH-gene, VH4-34. We therefore investigated whether the 9G4 idiotope was expressed on autoantibodies in patients with RA.Methodology/Principal FindingsSera from 19 patients with established RA and those with <1year history of untreated polyarthritis either resolving into RA (n = 42) or non-RA diagnosis (n = 31) were included. Autoantibodies to cyclic citrullinated peptides (CCP), RhF and co-expression of the 9G4 idiotope were measured by ELISA. 9G4 recognised a population of anti-CCP antibodies in the majority of sera from patients with established disease and also in samples from patients with early disaese. 9G4+RhF levels were generally lower and not associated with positivity for, or levels of 9G4+CCP.Conclusions/SignificanceThe persistence of 9G4+ immunoglobulins, of any isotype, in serum is rare. We describe here the novel finding of 9G4 expression on anti-CCP antibodies in patients from the earliest symptoms of RA through to established disease. Our results suggest that 9G4 expression on anti-CCP autoantibodies was not due to polyclonal expansion of VH4-34-encoded immunoglobulins. These studies may therefore provide a new focus for investigation into the evolution of the autoimmune response in RA patients.