Prevalence of anti-cyclic citrullinated peptide and anti-keratin antibodies in patients with primary Sjögren's syndrome

Epidemiology of Sjögren syndrome

Sjögren syndrome is a phenotypically varied autoimmune disorder that can occur alone in primary Sjögren syndrome or in association with other connective tissue diseases (CTDs), including rheumatoid arthritis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). The estimation of the prevalence and incidence of Sjögren syndrome varies depending on diagnostic criteria and study design, making it difficult to estimate geographical and temporal trends. Nonetheless, disease phenotype is influenced by geographical origin, which is a risk factor for systemic activity. Whether mortality in primary Sjögren syndrome is increased compared with that of the general population is not yet known, but extra-glandular manifestations, in particular lymphomas, are clear risk factors for mortality. In CTDs associated with Sjögren syndrome, lymphoma risk seems higher than that of patients with CTD alone, and there is potentially lower disease activity in SLE with Sjögren syndrome and in SSc with Sjögren syndrome than in SLE or SSc alone.

Are the cut-offs of the rheumatoid factor and anti-cyclic citrullinated peptide antibody different to distinguish rheumatoid arthritis from their primary differential diagnoses?

OBJECTIVE

Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-CCP) are commonly used for diagnosis of rheumatoid arthritis (RA), although other rheumatic diseases with arthritis can test positive. This study aimed to determine the cutoff values for RF and anti-CCP with the best diagnostic performance in a sample of patients with RA, compared with other rheumatic diseases.

METHODS

This was a descriptive, prospective study. EUROINMMUN enzyme-linked immunosorbent assays for RF isotypes immunoglobulin (Ig) A (IgA), IgG and IgM and third-generation assay IgG for anti-CCP were used in serum samples of patients with RA, other rheumatic diseases and healthy subjects. The cutoff with the best diagnostic performance was determined by the Youden Index and receiver operating characteristic analysis Results: Three hundred and thirty-two serum samples were analysed. The cutoffs proposed in our population were for RF in RA patients versus other rheumatic diseases, and healthy subjects IgM 135 IU/mL, for each disease, compared with RA, were psoriatic arthritis (Psa) IgA 47.2 IU/mL, clinically suspicious arthralgia (CSA) IgA 39.5 IU/mL, primary Sjögren's syndrome (pSS) IgM 180.6 IU/mL, systemic lupus erythematosus (SLE) IgA 42.6 IU/mL, primary fibromyalgia (pFM) IgM 68.6 IU/mL, osteoarthritis (OA) IgM 48 IU/mL, gout IgM 117 IU/mL and healthy IgM 16.3 IU/mL. For anti-CCP, in RA patients versus other rheumatic diseases, and healthy subjects 6.95 IU/mL, for each disease, compared with RA, were Psa 6.8 IU/mL, CSA 9.95 IU/mL, pSS 20.7 IU/mL, SLE 6 IU /mL, pFM 11.8 IU/mL, OA 11.9 IU/mL, gout 5 IU/mL and healthy 5 IU/mL.

CONCLUSION

Irrespective of the manufacturer's suggested cutoff, the RA versus differential diagnosis cutoffs must be considered.

Characteristics of primary Sjogren's syndrome with articular manifestations at initial treatment

Objectives

Articular manifestations have been reported in 19.3%-53.5% of patients with primary Sjogren's syndrome. Our aim was to profile the clinical characteristics of Chinese patients with primary Sjogren's syndrome who presented with articular manifestations at the time of initial treatment.

Methods

We conducted a retrospective study of 129 primary Sjogren's syndrome patients admitted to the second Affiliated Hospital of Dalian Medical University between April 2016 and December 2021 for initial treatment. Clinical and serological features, extra-articular involvement, and initial treatment were compared between primary Sjogren's syndrome patients with and without articular manifestations.

Results

Fifty-seven (44.2%) primary Sjogren's syndrome patients had articular manifestations (mean age at diagnosis: 53.4 years), of which 42 (73.7%) presented with symmetrical distribution, 21 (36.8%) patients had rheumatoid factor positivity, and 11 (20.0%) patients had anti-cyclic citrullinated peptide antibodies positivity (mean 6.8 RU/mL); imaging examinations showed no signs of structural damage in these patients. The presence of articular manifestations showed positive correlation with anti-cyclic citrullinated peptide antibody level (odds ratio (OR) 1.01, 95% confidence interval (CI): 1.00-1.02; p = 0.049), C-reactive protein level (OR 1.15, 95% CI: 1.10-1.20; p = 0.000), and European League Against Rheumatism Sjogren syndrome disease activity index scores (OR 1.18, 95% CI: 1.11-1.25; p = 0.000). Ninety (69.8%) primary Sjogren's syndrome patients received hydroxychloroquine therapy. Hydroxychloroquine treatment was significantly less frequently used in articular manifestation patients (35 (70.0%) vs 55 (85.9%); p = 0.038).

Conclusions

Symmetrical polyarthritis was the most common clinical manifestation of primary Sjogren's syndrome patients with articular manifestations in this cohort. Articular manifestations were associated with higher prevalence of C-reactive protein level, and European League Against Rheumatism Sjogren syndrome disease activity index score.

The Prevalence of Anticitrullinated Protein Antibodies in Older Poles-Results from a Population-Based PolSenior Study

Little is known about the occurrence of antibodies in older subjects. We analyzed the prevalence of anticitrullinated protein antibodies (anti-CCP) in a representative cohort of Polish older adults, participants of PolSenior substudy. Randomly selected 1537 serum samples of community-dwelling participants aged 65 and over. Questionnaires were completed by qualified interviewers and laboratory assessments served as a database for this analysis. The frequency of anti-CCP seropositivity (N = 50) was estimated at 3.25% (95% CI: 2.45-4.30%), being higher among women-4.05% (2.83-5.73%) than men-2.41% (1.48-3.86%). The frequency of anti-CCP seropositivity was decreasing with age from 4.29% in aged 65-74 years and 4.07% in 70-84 years to 1.50% in aged 85 years or above (p < 0.05). Hypoalbuminemia, inflammatory status (C-reactive protein >10 mg/dL or interleukin-6 ≥10 pg/mL), and female gender were associated with increased, while age ≥85 years with decreased risk of seropositivity. Multivariable logistic regression revealed that hypoalbuminemia, inflammatory status, and age ≥85 years were independently associated factors of anti-CCP seropositivity. The decreased frequency of anti-CCP seropositivity in the oldest old suggests shorter survival of the seropositive individuals who developed rheumatoid arthritis. It seems that low symptomatic RA remains frequently undiagnosed in older subjects.

Not all autoantibodies are clinically relevant. Classic and novel autoantibodies in Sjögren’s syndrome: A critical review

Sjögren’s syndrome (SjS) is a heterogeneous systemic disease. The abnormal responses to La/SSB and Ro/SSA of both B-cells and T-cells are implicated as well as others, in the destruction of the epithelium of the exocrine glands, whose tissue characteristically shows a peri-epithelial lymphocytic infiltration that can vary from sicca syndrome to systemic disease and lymphoma. Despite the appearance of new autoantibodies, anti-Ro/SSA is still the only autoantibody included in the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria and is used extensively as a traditional biomarker in clinical practice. The study and findings of new autoantibodies in SjS has risen in the previous decade, with a central role given to diagnosis and elucidating new aspects of SjS physiopathology, while raising the opportunity to establish clinical phenotypes with the goal of predicting long-term complications. In this paper, we critically review the classic and the novel autoantibodies in SjS, analyzing the methods employed for detection, the pathogenic role and the wide spectrum of clinical phenotypes.

Autoimmune markers in screening for orbital inflammatory disease

PURPOSE

Immunogenic causes of inflammation may be difficult to differentiate in the work-up of orbital inflammatory disease. The study aims to investigate the utility of autoimmune markers in the screening for orbital inflammation. Markers studied included angiotensin-converting enzyme (ACE), antinuclear antibody (ANA), anti-neutrophilic cytoplasmic autoantibodies (ANCA), extractable nuclear antigen (ENA), anti-cyclic citrullinated peptide (Anti-CCP) and anti-double stranded DNA antibody (Anti-dsDNA antibody).

METHODS

A retrospective single-centre study of consecutive patients with non-infective orbital inflammation screened for autoimmune markers at presentation. Serology was interpreted alongside clinical course and other investigations (e.g. radiographic features and histopathology). Tabulated data and Pearson's Chi-square allowed analysis of trends between serology, diagnosis and the decision to biopsy.

RESULTS

79 patients, between 1999 and 2021, were included (50 females, mean age was 50.4 ± 17.4 years). 28 (34.6%) patients had specific orbital inflammation and 53 (65.4%) patients had non-specific orbital inflammation (NSOI). Of the 12 patients with positive serology and a specific diagnosis, only 5 (41.7%) patients had concordant serological results. There was no association between serology results and the patient undergoing biopsy (P = 0.651). Serology was unable to exclude nor differentiate NSOI from other specific conditions and ANA had limited discriminatory value between specific conditions and NSOI.

CONCLUSION

Serological testing alone may not provide a clear direction for further investigation of orbital inflammation and a biopsy may occur independently of the serological results. The value of autoimmune markers may lie in subsequent follow-up as patients may develop suggestive symptoms after an indeterminate positive result or initially seronegative disease.

Prevalence of autoantibodies in pediatric patients with idiopathic pulmonary hemosiderosis: a scoping review of the literature in the period 1980-2021

Idiopathic pulmonary hemosiderosis (IPH) is a rare disease of unknown etiology. Due to the frequent findings of autoimmune antibodies - autoantibodies, immunologic causation of the diffuse alveolar hemorrhage in IPH has been proposed, to assess the prevalence/frequency and type of autoantibodies in pediatric patients with IPH. In addition, the patient demographics, diagnostic modalities used to diagnose IPH, treatment, and outcomes were also evaluated. Scoping review: The PubMed, Medline, and Embase databases were searched with appropriate MeSH terms to identify relevant papers consistent with the defined inclusion criteria. Thirteen observational studies comprising a total of 352 pediatric patients were included in this review. The majority of subjects were girls 217 out of 352 (61.6%). The mean and median ages of patients ranged from 3.1-6.5 years to 2.3-7 years, respectively. In the 10 studies that specified the number of patients in their cohorts with either at least one positive autoantibody or no antibody, the overall prevalence of autoantibodies was 76 out of 288 patients (26.4%). The prevalence of specific antibodies was as follows: ANA, 20.3%; ANCA, 17%; anti-dsDNA, 9.1%; RF, 12%; anti-SMA, 23.2%; and celiac antibodies, 25.9%. Cow's milk protein allergy was present in 16.2% of the children. The significance of an association between IPH and the presence of autoantibodies has not been clarified. The autoantibodies could be suggestive of an overall immune dysregulation rather than causation. However, limited evidence based on a single study suggests that the presence of ANA may be associated with a higher risk of recurrence and worse outcomes. Further research, including prospective studies, will be crucial to explore a possible genetic linkage between vasculitides, systemic rheumatologic diseases, and IPH.

Protein-Based Immunome Wide Association Studies (PIWAS) for the Discovery of Significant Disease-Associated Antigens

Identification of the antigens associated with antibodies is vital to understanding immune responses in the context of infection, autoimmunity, and cancer. Discovering antigens at a proteome scale could enable broader identification of antigens that are responsible for generating an immune response or driving a disease state. Although targeted tests for known antigens can be straightforward, discovering antigens at a proteome scale using protein and peptide arrays is time consuming and expensive. We leverage Serum Epitope Repertoire Analysis (SERA), an assay based on a random bacterial display peptide library coupled with next generation sequencing (NGS), to power the development of Protein-based Immunome Wide Association Study (PIWAS). PIWAS uses proteome-based signals to discover candidate antibody-antigen epitopes that are significantly elevated in a subset of cases compared to controls. After demonstrating statistical power relative to the magnitude and prevalence of effect in synthetic data, we apply PIWAS to systemic lupus erythematosus (SLE, n=31) and observe known autoantigens, Smith and Ribosomal protein P, within the 22 highest scoring candidate protein antigens across the entire human proteome. We validate the magnitude and location of the SLE specific signal against the Smith family of proteins using a cohort of patients who are positive by predicate anti-Sm tests. To test the generalizability of the method in an additional autoimmune disease, we identified and validated autoantigenic signals to SSB, CENPA, and keratin proteins in a cohort of individuals with Sjogren’s syndrome (n=91). Collectively, these results suggest that PIWAS provides a powerful new tool to discover disease-associated serological antigens within any known proteome.

The adaptive immune response to porous regenerated keratin as a bone graft substitute in an ovine model

Reconstituted keratin is a novel bone graft material when prepared as a rigid scaffold. Understanding the immunogenicity of this material is important to determine whether this substance is a viable surgical option. Previous studies have shown no innate immune system activation in response to reconstituted keratin implants. To examine antibody-mediated immune responses to reconstituted keratin implants, bone and blood samples were taken from twelve sheep with surgically created tibial defects containing such implants. RT-PCR was used to detect mRNA of the inflammatory marker SOCS 3 in local bony tissue, and a novel immunohistochemistry assay developed to detect antikeratin antibodies in serum. Two animals were sacrificed per time-point at weeks 1, 2, 4, 6, 8 and 12. Time points for serum analysis included baseline (pre-surgery) and all other time points; mRNA analysis examined samples from all time points. No upregulation in antikeratin antibodies or SOCS 3 mRNA was observed at any time point, indicating that reconstituted keratin implants do not trigger an adaptive immune response in vivo in an ovine model. These findings provide the platform for further development of keratin implants in other mammalian models to define its immunogenic profile and safety.

Characterizing hand and wrist ultrasound pattern in primary Sjögren's syndrome: a case-control study

INTRODUCTION/OBJECTIVES

To evaluate the clinical relevance of high-resolution hand and wrist ultrasound (US) findings and their possible associations with anti-citrullinated peptide antibodies in primary Sjögren's syndrome (pSS).

METHODS

Ninety-seven consecutive pSS patients (American-European Consensus Group, 2002) without meeting the American College of Rheumatology (ACR) criteria (1987) for rheumatoid arthritis (RA); 20 RA patients (ACR/European League Against Rheumatism (EULAR) criteria, 2010); and 80 healthy individuals with comparable age, gender, and ethnicity were enrolled in a case-control study. Disease activity was assessed by EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI). US was performed by one expert blinded to anti-CCP, anti-MCV, and IgM rheumatoid factor tested by ELISA.

RESULTS

Frequencies of grade 3 synovitis (9.3 vs. 0%, p = 0.004), tenosynovitis (36.1 vs. 3.8%, p < 0.001), and erosions (27.8 vs. 7.5%, p = 0.001) on US were higher in pSS patients than in healthy controls. ESSDAI presented a moderate correlation with the synovitis number (p = 0.001) and tenosynovitis (p < 0.001). Most pSS patients with erosions on US (81.5%) had negative anti-CCP. Nevertheless, anti-CCP ≥ 3× cut-off value was associated with the presence of erosions in pSS (p = 0.026). Erosions in pSS were mainly small size contrasting with moderate/large size in RA (p < 0.001), and positive power Doppler synovitis predominated in RA (p < 0.001).

CONCLUSIONS

US identified significant frequencies of grade 3 synovitis, tenosynovitis, and erosions in pSS. Synovitis and tenosynovitis numbers were correlated with ESSDAI. Association between erosions on US and anti-CCP (high titers) in pSS possibly identifies a subgroup with severe arthritis. These findings suggest that US is a useful method for assessing joint involvement in pSS.Key Points• US identified significant frequencies of grade 3 synovitis, tenosynovitis, and erosions in pSS patients in comparison with age- and race-healthy individuals.• Numbers of synovitis and tenosynovitis on US were correlated with ESSDAI values.• Most pSS patients with erosions on US were negative for anti-CCP, but anti-CCP ≥ 3× cut-off value was associated with the presence of erosions in this disease.• Erosions in pSS were mainly small size contrasting with moderate/large size in RA, and positive power Doppler synovitis predominated in RA.

Arthritis in primary Sjögren's syndrome: Characteristics, outcome and treatment from French multicenter retrospective study

OBJECTIVE

To describe the characteristics and the outcome of primary Sjögren Syndrome (pSS) associated arthritis and to compare the efficacy of different therapeutic regimen.

METHODS

We conducted a retrospective study using Club Rhumatisme and Inflammation (CRI) and French Internal Medicine Society (SNFMI) networks. All patients with a diagnosis of pSS and at least one episode of clinical and/or echographic synovitis were included. Patients with synovitis (cases) were compared to pSS patients without synovitis (controls).

RESULTS

57 patients (93% women) were included with a median age of 54 years [45-63]. Patients with synovitis had more frequently lymph node enlargement (12.3% vs. 1.8%, p = .007) and a higher ESSDAI score (8 [6-12] vs. 2 [1-4], p < .0001). There was no difference concerning CRP levels, rheumatoid factor and cyclic citrullinated peptide (CCP)-antibodies positivity. Among 57 patients with synovitis, 101 various treatment courses have been used during the follow-up of 40 [22.5-77] months. First treatment course consisted in steroids alone (3.5%), steroids in association (79%) with hydroxychloroquine (HCQ) (49%), methotrexate (MTX) (35%), rituximab (RTX) (5.3%) or other immunosuppressive drugs (7%). HCQ, MTX, and RTX were associated with a significant reduction of tender and swollen joint count, and a significant steroids-sparing effect. No difference could be shown for the joint response between these treatment regimens.

CONCLUSION

pSS articular manifestations may include synovitis which could mimic rheumatoid arthritis but differ by the absence of structural damage. Even if the use of HCQ, MTX, and RTX seem to be effective for joint involvement, the best regimen remains to be determined.

The findings of musculoskeletal ultrasonography on primary Sjögren's syndrome patients in childhood with articular manifestations and the impact of anti-cyclic citrullinated peptide antibody

Objective: We researched the findings of musculoskeletal ultrasound sonography (MSUS) on primary Sjogren's syndrome in childhood (pSS-C) with articular manifestations. The correlation of rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) were investigated to evaluate the usefulness of MSUS on their articular prognosis. Method: The objective patients are pSS-C cases who visited our hospital complaining joint pain and/or joint swelling and for whom MSUS was performed. Result: Eight patients included 6 female and 2 male, 5 RF-positive patients and 3 ACPA- positive patients. The mean age of onset was 11.1 ± 3.0 years (352 physical joint findings and 284 MSUS findings. The number of joints found clinical articular manifestations was 58/352 joints, and arthritis detected by MSUS was 30/284 joints). In multivariate analysis, the odds ratio of clinical articular manifestations was significant high in RF-positivity (2.9, 95%CI 1.5-6.2). The odds ratio of arthritis detected by MSUS in ACPA-positivity was significant high (3.7, 95%CI 1.5-11.6), although odds ratio in RF-positivity had no statistical significance and a similar trend was seen in odds ratios of subclinical arthritis (4.9, 95%CI 1.6-18.0). Conclusion: It was indicated that MSUS is useful for pSS-C. ACPA-positive pSS-C patients have arthritis and subclinical arthritis more frequently than ACPA-negative patients.

Prognostic value of Sjögren's syndrome autoantibodies

Sjögren's syndrome is in part considered an autoimmune disease because patient sera contain antibodies binding self-structures. In fact, in addition to anti-Ro (or SSA) and anti-La (or SSB), which are included in the classification criteria, there are a wide variety of autoantibodies found among these patients. We reviewed English-language MEDLINE sources. Anti-Ro and anti-La found among healthy individuals, including mothers giving birth to infants with neonatal lupus, predicts future connective tissue disease. Those with Sjögren's syndrome can be divided into two groups; patients with only exocrine gland involvement and those with systemic disease. The presence of anti-Ro/La is associated with systemic, extraglandular disease. Rheumatoid factor is also associated with extraglandular disease while anti-cyclic citrullinated peptide (CCP) is likely associated with inflammatory arthritis and progression to rheumatoid arthritis. Anti-mitochondrial antibodies are uncommon but predict progression to primary biliary cirrhosis. Cryoglobulinemia is found in excess among those with non-Hodgkin's lymphoma. Determination of autoantibodies on the sera of Sjögren's syndrome patients has prognostic implications for Sjögren's syndrome itself as well as associated diseases.

Anti-citrullinated protein antibodies and arthritis in Sjögren's syndrome: a systematic review and meta-analysis

OBJECTIVE

The presence of anti-citrullinated protein antibodies (ACPAs) in primary Sjögren's syndrome (pSS) ranges from 3% to 9.9%; however, there is no agreement about their clinical significance. Our aim was to systematically review the literature regarding the association of arthritis and ACPAs in pSS and their role in the development of rheumatoid arthritis (RA).

METHOD

A comprehensive search of MEDLINE, ISI Web of Knowledge, and Cochrane Library from inception until June 2016 was undertaken using the combination of two or three of the keywords: primary Sjögren's syndrome, Sjögren's syndrome, arthritis, synovitis, arthropathy, anti-cyclic citrullinated peptide antibodies, and anti-citrullinated protein antibody - ACPA. No language restriction was used. Studies were included if they: assessed the association of arthritis and ACPAs, had sufficient data to construct a two-by-two table, tested immunoglobulin G ACPA by any method, and included patients with pSS according to a validated set of classification criteria. We used a random effects model and evaluated the heterogeneity and publication bias.

RESULTS

Ten studies were included (involving 1322 patients). We found a pooled odds ratio of 4.42 (95% confidence interval 1.15-16.94, p = 0.03). The test for heterogeneity was I² = 0.87. Publication bias was not observed. Based on data from three studies, 33 of 58 pSS patients with ACPAs (57%) developed RA compared with none of 598 pSS patients with negative ACPA (p < 0.000001).

CONCLUSION

Patients with pSS disclosing ACPAs are prone to arthritis as part of the clinical spectrum of the disease, but are also at risk of developing RA.

Clinical practice guideline for Sjögren's syndrome 2017

OBJECTIVES

The objective of this study is to develop clinical practice guideline (CPG) for Sjögren's syndrome (SS) based on recently available clinical and therapeutic evidences.

METHODS

The CPG committee for SS was organized by the Research Team for Autoimmune Diseases, Research Program for Intractable Disease of the Ministry of Health, Labor and Welfare (MHLW), Japan. The committee completed a systematic review of evidences for several clinical questions and developed CPG for SS 2017 according to the procedure proposed by the Medical Information Network Distribution Service (Minds). The recommendations and their strength were checked by the modified Delphi method. The CPG for SS 2017 has been officially approved by both Japan College of Rheumatology and the Japanese Society for SS.

RESULTS

The CPG committee set 38 clinical questions for clinical symptoms, signs, treatment, and management of SS in pediatric, adult and pregnant patients, using the PICO (P: patients, problem, population, I: interventions, C: comparisons, controls, comparators, O: outcomes) format. A summary of evidence, development of recommendation, recommendation, and strength for these 38 clinical questions are presented in the CPG.

CONCLUSION

The CPG for SS 2017 should contribute to improvement and standardization of diagnosis and treatment of SS.

Activation of Peptidylarginine Deiminase in the Salivary Glands of Balb/c Mice Drives the Citrullination of Ro and La Ribonucleoproteins

The goal of the present study was to determine whether peptidylarginine deiminase PAD2 and PAD4 enzymes are present in Balb/c mouse salivary glands and whether they are able to citrullinate Ro and La ribonucleoproteins. Salivary glands from Balb/c mice were cultured in DMEM and supplemented with one of the following stimulants: ATP, LPS, TNF, IFNγ, or IL-6. A control group without stimulant was also evaluated. PAD2, PAD4, citrullinated peptides, Ro60, and La were detected by immunohistochemistry and double immunofluorescence. PAD2 and PAD4 mRNAs and protein expression were detected by qPCR and Western blot analysis. PAD activity was assessed using an antigen capture enzyme-linked immunosorbent assay. LPS, ATP, and TNF triggered PAD2 and PAD4 expression; in contrast, no expression was detected in the control group (p < 0.001). PAD transcription slightly increased in response to stimulation. Additionally, PAD2/4 activity modified the arginine residues of a reporter protein (fibrinogen) in vitro. PADs citrullinated Ro60 and La ribonucleoproteins in vivo. Molecular stimulants induced apoptosis in ductal cells and the externalization of Ro60 and La ribonucleoproteins onto apoptotic membranes. PAD enzymes citrullinate Ro and La ribonucleoproteins, and this experimental approach may facilitate our understanding of the role of posttranslational modifications in the pathophysiology of Sjögren's syndrome.

The Clinical Application of Anti-CCP in Rheumatoid Arthritis and Other Rheumatic Diseases

Rheumatoid arthritis (RA) is a common rheumatic disease in Caucasians and in other ethnic groups. Diagnosis is mainly based on clinical features. Before 1998, the only serological laboratory test that could contribute to the diagnosis was that for rheumatoid factor (RF). The disease activity markers for the evaluation of clinical symptoms or treatment outcome were the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). As a matter of fact, the diagnosis of early RA is quite impossible, as the clinical criteria are insufficient at the beginning stage of the disease. In 1998, Schelleken reported that a high percentage of RA patients had a specific antibody that could interact with a synthetic peptide which contained the amino acid citrulline. The high specificity (98%) for RA of this new serological marker, anti-cyclic citrullinated antibody (anti-CCP antibody), can be detected early in RA, before the typical clinical features appear. The presence or absence of this antibody can easily distinguish other rheumatic diseases from RA. Additionally, the titer of anti-CCP can be used to predict the prognosis and treatment outcome after DMARDs or biological therapy. Therefore, with improvement of sensitivity, the anti-CCP antibody will be widely used as a routine laboratory test in the clinical practice for RA.

Antibodies against citrullinated alpha enolase peptides in primary Sjogren's syndrome

Citrullinated alpha enolase (CEP-1) has been designated as a major antigenic target of antibodies against citrullinated proteins (ACPA) in patients with rheumatoid arthritis (RA). Our aim is to determine the prevalence of anti-CEP-1 in a cohort of ACPA positive (ACPA+) primary Sjogren's syndrome (pSS) patients. Anti-CEP1 titers were determined by ELISA in sera from 15 ACPA+ and 45 ACPA- age/sex matched pSS; 12 ACPA+ RA patients and 30 healthy controls (HC). Increased anti-CEP-1 antibody titers were detected in nine out of the 15 (60%) ACPA+ pSS patients and 5 out of 12 (41.7%) ACPA+ RA patients; no reactivities were detected in ACPA- pSS patients and HC. Anti-CEP-1 antibodies in the setting of pSS were associated with higher urine pH levels at baseline. CEP-1 is a major antigenic target of ACPA in patients with pSS characterizing a subgroup with distinct laboratory features.

Serum Biomarkers for Discrimination between Hepatitis C-Related Arthropathy and Early Rheumatoid Arthritis

In the present study, we aimed to estimate the concentrations of cytokines (interleukin 6, IL-6, tumor necrosis factor-α, TNF-α) and auto-antibodies (rheumatoid factor IgM isotype, IgM-RF, antinuclear auto-antibodies, ANA, anti–cyclic citrullinated peptide antibodies IgG isotype, IgG anti-CCP3.1, anti-cardiolipin IgG isotype, IgG anti-aCL) in serum of patients with eRA (early rheumatoid arthritis) and HCVrA (hepatitis C virus-related arthropathy) and to assess the utility of IL-6, TNF-α together with IgG anti-CCP and IgM-RF in distinguishing between patients with true eRA and HCVrA, in the idea of using them as differential immunomarkers. Serum samples were collected from 54 patients (30 diagnosed with eRA-subgroup 1 and 24 with HCVrA-subgroup 2) and from 28 healthy control persons. For the evaluation of serum concentrations of studied cytokines and auto-antibodies, we used immunoenzimatique techniques. The serum concentrations of both proinflammatory cytokines were statistically significantly higher in patients of subgroup 1 and subgroup 2, compared to the control group (p < 0.0001). Our study showed statistically significant differences of the mean concentrations only for ANA and IgG anti-CCP between subgroup 1 and subgroup 2. We also observed that IL-6 and TNF-α better correlated with auto-antibodies in subgroup 1 than in subgroup 2. In both subgroups of patients, ROC curves indicated that IL-6 and TNF-α have a higher diagnostic utility as markers of disease. In conclusion, we can say that, due to high sensitivity for diagnostic accuracy, determination of serum concentrations of IL-6 and TNF-α, possibly in combination with auto-antibodies, could be useful in the diagnosis and distinguishing between patients with true eRA and HCV patients with articular manifestation and may prove useful in the monitoring of the disease course.

Autoantibodies, detection methods and panels for diagnosis of Sjögren's syndrome

The presence of autoantibodies is one of several hallmarks of Sjögren's Syndrome, the detection of serum autoantibodies has a central role in the diagnosis and classification of Sjögren's syndrome. In this review, we will discuss autoantibodies that are helpful in the diagnosis of Sjögren's syndrome. This includes the traditional autoantibodies for disease classification (ANA, Anti-Ro/SSA, Anti-La/SSB, RF), autoantibodies identified from mouse models (Anti-SP1, Anti- PSP, Anti-CA6, and anti-alpha fodrin) and autoantibodies associated with other autoimmune disease (ACA, AMA, and Anti-CCP). We will also review the methods for the detection of autoantibodies and associated challenges for clinical results reporting. The significance of using an autoantibody panel for the diagnosis of SS will be also be reviewed.

Laboratory Investigations for Diagnosis of Autoimmune and Inflammatory Periocular Disease: Part II

PURPOSE

To review the important laboratory serological investigations routinely performed for the diagnosis of autoimmune and inflammatory diseases of the orbit and ocular adnexa.

METHODS

Review of the literature as well as personal clinical experience of the authors. Due to the extensive nature of the topic, the review has been split into 2 parts. Part I covers thyroid eye disease, IgG4-related disease, and myasthenia gravis. In part II of the review, sarcoidosis, vasculitis, Sjögren syndrome, and giant cell arteritis will be discussed.

RESULTS

Several relatively specific serologic tests are available for the diagnosis of a variety of inflammatory and serologic diseases of the orbit.

CONCLUSION

In cases of limited orbital or sino-orbital disease, serologic testing may be negative in a significant number of patients. Specifically, the clinician should be wary of ruling out limited orbital sarcoid or sinoorbital granulomatosis with polyangiitis based on serologic testing alone. Part I of this review has covered serologic testing for thyroid eye disease, IgG4-related disease, and myasthenia gravis. In part II, the authors discuss serologic testing for sarcoidosis, vasculitis, Sjögren syndrome (SS), and giant cell arteritis (GCA).

Factors Associated with Erosive Arthritis in Rheumatoid Arthritis and Other Connective Tissue Diseases: A Retrospective Study From a Southern Chinese Population

OBJECTIVE

To investigate the clinical predictors of erosive arthritis (EA) in patients with rheumatoid arthritis (RA) and other connective tissue diseases.

METHODS

Four hundred and one consecutive patients with newly diagnosed RA between January 2010 and January 2013 were enrolled in the study. During the study period, 729 consecutive patients with non-RA connective tissue diseases were also included, and a cross-sectional study was performed. Medical records were reviewed. Only those patients with data for 2 years were considered in the analysis (338).

RESULTS

Erosive arthritis was noted in 60.4% (204 /338) of patients with RA and occurred early in RA. The multivariate logistic regression analysis indicated that rheumatoid nodules, anemia, and positive anticyclic citrullinated peptide antibody (ACPA) were strongly associated factors for the occurrence of EA in RA patients. Erosive arthritis was also noted in 1.5% of patients with SLE, 5.8% of patients with primary Sjögren syndrome, and 9.1% (3/33) of patients with systemic sclerosis. When compared with patients without EA, high level and prominently higher positive rate of ACPA was found in these patients with EA. On receiver operating characteristic curve analysis, ACPA exhibited a maximum sensitivity with a cutoff value of 1.6 U/mL and 0.6 U/mL for RA and SLE patients, respectively.

CONCLUSION

Erosive arthritis had a high prevalence in Chinese RA patients and occurred early. Anemia, rheumatoid nodules, and ACPA were associated with EA in RA. Erosive arthritis also could be detected in SLE, primary Sjögren syndrome, and systemic sclerosis. Anticyclic citrullinated peptide antibodies were also associated with EA in these diseases. Intensive monitoring for erosions was recommended for RA patients with a cutoff of ACPA greater than 1.6 U/mL and greater than 0.6 U/mL for SLE patients.

Autoantibodies in Sjögren's Syndrome

We compiled information on antibodies in Sjögren syndrome, focusing more on clinical manifestations associated with anti-Ro/SSA and anti-La/SSB antibodies and studies regarding novel antibodies. We reviewed previous as well as most recent studies with the subject heading Sjogren in combination with antibodies and congenital heart block (CHB). Almost half of asymptomatic mothers giving birth to children with CHB ultimately develop Sjögren. We discussed studies concerning the presence of antibodies predating clinical manifestations of disease. Studies in the future are required to ascertain the pathogenic mechanisms associated with these antibodies and the specific clinical manifestation related to new autoantibodies.

A phase II investigator-initiated pilot study with low-dose cyclosporine A for the treatment of articular involvement in primary Sjögren's syndrome

This study aims to investigate the efficacy and safety of low-dose cyclosporine A (CyA) in patients with primary Sjögren's syndrome (pSS) and articular involvement. This phase II open-label clinical study included 30 patients meeting the American-European Consensus group criteria for pSS with active joint involvement under stable symptomatic therapy. Treatment consisted of approximately 2 mg kg(-1) body weight of CyA day(-1) over a period of 16 weeks. The primary endpoint was defined as a reduction in the number of painful and/or swollen joints at end of treatment (EOT). Secondary endpoints included the changes in general health, sicca symptoms, European League Against Rheumatism (EULAR) Sjögren's Syndrome Disease Activity Index (ESSDAI), arthrosonography, and safety profile. At baseline (BL), the mean number of tender joints (68 count) was 16.2 (±13.2) and at EOT 10.4 (±11.9; p = 0.002). The mean number of swollen joints (66 counts) was reduced from 3.2 (±3.3) at BL to 1.3 (±3.2) at EOT (p < 0.001). Overall, 21 (70 %) and 13 (43.3 %) patients had a reduction of two or more tender and swollen joints, respectively, in the 68/66 joint counts. The disease activity score (DAS28) showed a statistically and clinically meaningful decrease over the 16-week period of treatment. Treatment was well tolerated, and adverse events were consistent with the known safety profile of CyA (e.g., hypertension, headache). In this pilot study, promising effects of low-dose CyA treatment on articular involvement were observed in patients with pSS justifying further controlled studies in this indication. No new or unexpected safety observations were made.

TRIAL REGISTRATION

Low-Dose Cyclosporin A in Primary Sjögren Syndrome (CYPRESS), ClinicalTrials.gov Identifier: NCT01693393 .

Previous diagnosis of Sjögren's Syndrome as rheumatoid arthritis or systemic lupus erythematosus

OBJECTIVE

The diagnosis of SS is often difficult and many patients are symptomatic for years with other diagnoses before confirmation of SS. Our aim was to determine whether overlapping clinical and serologic features with RA and SLE may in part drive the misdiagnoses.

METHODS

A total of 1175 sicca patients were evaluated in a multidisciplinary clinic and classified as having SS based on the American-European Consensus Group Criteria. They were interrogated for a past history of suspicion or diagnosis of RA, SLE or SSc. These diseases were confirmed or ruled out by applying the corresponding classification criteria if the patients responded affirmatively.

RESULTS

Of these, 524 (44.6%) subjects reported previous diagnosis or suspicion of RA, SLE or SSc, which was confirmed in 130 (24.8%) but excluded in 394 (75.2%) subjects. Of those previously diagnosed with another illness, 183 (34.9%) met the criteria for primary SS. RF was present in 70/191 patients with previous diagnosis of RA compared with 445/845 without a prior RA diagnosis (P = 3.38E-05), while 128/146 with a diagnosis of SLE had positive ANA compared with 622/881 without the diagnosis (P = 8.77E-06). Age also influenced former diagnoses: people with suspected RA were older than those without the diagnosis (P = 5.89E-06), while patients with SLE suspicion were younger (P = 0.0003). Interestingly, the previous diagnoses did not significantly delay a final classification of SS.

CONCLUSION

Among subjects classified as SS, the presence of a positive ANA or RF was associated with a previous, apparently erroneous diagnosis of SLE or RA, respectively.

Pain in primary Sjögren's syndrome

Joint and muscle pain are commonly observed in patients with primary Sjögren's syndrome (pSS). Different types of pain can be distinguished, that is, articular pain, neuropathic pain and widespread pain. Articular pain is due to more or less evident synovitis, usually involving peripheral joints such as hand joints, wrists, knees and ankles. Drugs used to treat rheumatoid arthritis, or lupus synovitis, are also employed for articular involvement in pSS. Pure sensory neuropathies and, more often, small fibre neuropathies are responsible for neuropathic pain in pSS. This is usually localised in the legs and arms with a characteristic glove or sock distribution. Widespread pain, often assuming the features of fibromyalgia, has also been reported in patients with pSS. The pathological mechanisms underlying both neuropathic pain and widespread (fibromyalgia) pain in pSS have not been so far completely clarified.

ACPA-positive primary Sjögren's syndrome: true primary or rheumatoid arthritis-associated Sjögren's syndrome?

Objectives

Anticyclic citrullinated protein antibodies (ACPA) are highly specific of rheumatoid arthritis (RA). However, they have also been detected in 5–10% of primary Sjögren's syndrome (pSS). We compared ACPA-positive and negative patients with pSS and assessed the risk of evolution to RA.

Patients and methods

ACPA-positive and negative patients with pSS were included in this study. For ACPA-positive patients, clinical and radiological re-evaluation was systematically performed after at least 5 years of follow-up. Diagnosis was reassessed at the end of the follow-up to identify patients that developed RA according to the American College of Rheumatology 1987 classification criteria.

Results

At inclusion in the cohort 16 patients with pSS were ACPA positive and 278 were ACPA negative. ACPA-positive patients, had more frequently arthritis (43.7% vs 12.2%; p=0.003) but not arthralgias. They also had more frequent lung involvement (25% vs 8.1%; p=0.05). After median follow-up of 8 (5–10) years, 7/16 (43.8%) patients developed RA including 5 (31.25%) with typical RA erosions. Elevation of acute phase reactants at inclusion was the only parameter associated with progression to erosive RA.

Conclusions

Median term follow-up of ACPA-positive patients with pSS showed that almost half of them developed RA, particularly in the presence of elevation of acute phase reactants. These results support the usefulness of a close radiological monitoring of these patients for early detection of erosive change not to delay initiation of effective treatment. Indeed, number of these patients with ACPA-positive pSS may actually have RA and associated SS.

Clinical aspects of indirect immunofluorescence for autoimmune diseases

Because the most common term used in conversations considering autoimmunity is autoantibodies, it is well-expected that the indirect immunofluorescence assay, which detects antibodies directed against various antigens, is one of our most impressive techniques for investigating autoimmune diseases (AIDs). Roughly speaking, the current literature corroborates that this immunopathologic investigation means that autoantibodies detection makes a considerable contribution to both diagnostic and prognostic aspects of AIDs in the clinical setting. However, it varies between different AIDs, autoantibodies, ethnicities or detection methodologies. Directly focusing on the indirect immunofluorescence assay, we present evidence to support this multidimensional variation regarding the subject via reviewing briefly the best-investigated autoantibodies in the well-documented AIDs, including vasculitis, inflammatory bowel disease, scleroderma, autoimmune hepatitis, primary biliary cirrhosis, systemic lupus erythematosus and Sjögren's syndrome.

Anticyclic Citrullinated Peptide Antibodies in Rheumatoid and Nonrheumatoid Rheumatic Disorders: Experience with 1162 Patients

Objective.

Anticyclic citrullinated peptide antibodies (anti-CCP) are considered specific markers of rheumatoid arthritis (RA) and have been included in the revised classification criteria for RA diagnosis. However, these antibodies have also been detected in patients with other types of chronic inflammatory rheumatism. Our objectives were to identify the prevalence of positive anti-CCP patients in non-RA diseases, to determine the diagnostic value of anti-CCP for the diagnosis of RA, to specify the clinical characteristics of non-RA patients positive for anti-CCP, and to determine the discriminatory value of the levels of anti-CCP in patients among the various diseases.

Methods.

We carried out an observational and descriptive study. All the determinations of anti-CCP requested by the 2 rheumatology departments at Cochin Hospital over a period of 18 months were analyzed. Such determinations were requested for 1162 patients in total. Anti-CCP levels were determined with the Euro Diagnostica ELISA kit, with values ≥ 25 U for this test being considered positive. The diagnosis of rheumatic conditions was the responsibility of the treating physician.

Results.

Anti-CCP antibodies were detected in 357 (30.7%) of the 1162 patients. The prevalence of anti-CCP was 292/417 (70.0%) in RA, 13/122 (10.6%) in patients with psoriatic arthritis, 13/62 (20.9%) in patients with unclassified rheumatism, 11/33 (33.3%) in patients with primary Sjögren syndrome, 5/30 (16.6%) in patients with systemic lupus erythematosus, 3/28 (10.7%) in patients with mixed connective tissue disorder, 3/36 (8.3%) in patients with systemic sclerosis, 7/44 (15.9%) in patients with juvenile arthritis, and 6/220 (2.7%) in patients with noninflammatory diseases. In the population of patients positive for anti-CCP, mean anti-CCP levels were 869.4 (± 978.4) U/ml, with no significant difference between RA [854.8 (± 959.8) U/ml] and any of the non-RA conditions [922.7 (± 1070.0) U/ml].

Conclusion.

Anti-CCP are a hallmark of RA, but may be observed in other inflammatory, systemic, or mechanical diseases. In this large cohort of patients, the presence of second-generation anti-CCP (anti-CCP2) antibodies is useful in diagnosing RA (70% sensitivity, 91.3% specificity), but examining the levels of these antibodies does not appear to offer further discriminatory power among patients who are anti-CCP2-positive.

Anti-cyclic citrullinated peptide antibodies in ulcerative colitis, and its relation with disease activity

BACKGROUND

Ulcerative colitis an inflammatory bowel disease (IBD) and chronically idiopathic immune related that associates with extraintestinal manifestations such as arthritis. Despite of the highly specificity of anticyclic citrullinated peptide (CCP) antibodies for rheumatoid arthritis, their role in IBD remains unclear. There are only a few studies on the prevalence of anti-CCP antibodies in patients with IBD. This study aimed to assess the prevalence of anti- CCP antibodies in ulcerative colitis and to investigate possible associations with their clinical and laboratory characteristics Methods: In this cross-sectional study, 93 consecutive patients with ulcerative colitis referred to gastroenterology clinics in Razi referral hospital of Rasht, Iran, from September 2010 to September 2011. Rheumatologic examination, demographic data and clinical presentation of patients were recorded on specially prepared data sheets. Blood sample was collected for assessment of anti-CCP and other laboratory tests. Data were analyzed by the Chi square test, Fisher Exact test and student t test, using the SPSS 20 software for Windows, and P value less than 0.05 was considered significant.

RESULTS

Of 93 patients, anti-CCP antibodies detected in 10.8% of cases (CI 95%: 4.5-17.1%). There were a significant relation between the prevalence of anti CCP positivity and aphthous ulcers and ocular manifestations whereas other parameters were not significantly related.

CONCLUSION

Anti CCP may have a possible role in some ulcerative colitis manifestations but there was no association between the presence of these antibodies and activity or extension of inflammatory colitis. We suggest other studies especially molecular studies to investigate other aspects of these antibodies in IBD patients.

Anti-cyclic citrullinated Peptide antibody is associated with interstitial lung disease in patients with rheumatoid arthritis

OBJECTIVE

Patients with rheumatoid arthritis (RA) are at risk to develop RA-associated interstitial lung disease (RA-ILD). This retrospective study aimed to investigate the potential association of the positivity of serum anti-cyclic citrullinated peptide antibody (anti-CCP2) and rheumatoid factor (RF) with RA-ILD in RA patients.

METHODS

A total of 285 RA patients were recruited at the inpatient service of Peking Union Medical College Hospital in China between 2004 and 2013. Individual patients were evaluated for the evidence of ILD. The concentrations of serum anti-CCP2 and RF in individual patients were measured. The potential risk factors for ILD in RA patients were assessed by univariate and multivariate models.

RESULTS

There were 71 RA patients with RA-ILD, accounting for 24.9% in this population. The positive rates of anti-CCP2 and RF in the patients with RA-ILD were significantly higher than that in the patients with RA-only (88.7% vs. 67.3%, p<0.001; 84.5% vs. 70.6%, p = 0.02, respectively). Univariate and multivariate logistic regression analysis revealed that RA patients with positive serum anti-CCP2, but not RF, were associated with an increased risk of ILD (crude odds ratio [cOR] 3.83, 95% confidence interval [CI] 1.74-8.43, p<0.001; adjusted odds ratio [aOR] 3.50, 95% CI 1.52-8.04, p<0.001).

CONCLUSION

Our findings suggest that positive serum anti-CCP2, but not RF, may be associated with RA-ILD in RA patients.

A comprehensive review of autoantibodies in primary Sjögren's syndrome: clinical phenotypes and regulatory mechanisms

Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by periepithelial lymphocytic infiltrates in affected tissues and the production of plethora of autoantibodies. Among them autoimmune responses against Ro/SSA and La/SSB are of major importance since their detection is routinely used for disease diagnosis and clinical characterization. Although the exact mechanisms underlying disease pathogenesis are not fully understood, the important role of salivary gland epithelial cells (SGEC) in the initiation and development of the local immune responses is well-established. SGECs are also capable to mediate the exposure of the Ro/SSA and La/SSB autoantigens to the immune system by elevated apoptosis and autoantigen release in apoptotic bodies and/or by the secretion of autoantigen-containing exosomes. The expression of these autoantigens in epithelial cells appears to be tightly regulated. Up-to-date, signaling of certain innate immunity receptors, such as TLR3, appear to be implicated in the regulation of Ro/SSA and La/SSB expression by SGECs, whereas the deregulated expression of certain miRNAs that are predicted to target them in SS patients suggests a regulatory feedback at the post-transcriptional level. In the periphery, the humoral autoimmune responses are further regulated by the development of an active network of idiotypic-antiidiotypic antibodies. The plethora of mechanisms suggests that autoimmune humoral responses in SS are tightly regulated. In this review, the major humoral autoimmune responses, recent advances on the role of epithelial cells in their development, as well as possible regulatory mechanisms will be discussed.

Joint involvement in primary Sjögren's syndrome: an ultrasound "target area approach to arthritis"

Objective. To characterize the ultrasound (US) pattern of joint involvement in primary Sjögren's syndrome (pSS). Methods. Seventeen patients with pSS, 18 with secondary Sjögren's syndrome (sSS), and 17 healthy controls underwent US examinations of various articular regions. Synovitis (synovial hypertrophy/joint effusion), power Doppler (PD) signals, and erosions were assessed. Results. In patients with pSS, synovitis was found in the metacarpophalangeal joints (MCP, 76%), wrists (76%), and knees (76%), while the proximal interphalangeal joints, elbows, and ankles were mostly unscathed. Intra-articular PD signals were occasionally detected in wrists (12%), elbows (6%), and knees (6%). Erosions were evident in the wrists of three (18%) patients with pSS, one of these also having anti-cyclic citrullinated peptide (anti-CCP) antibodies. While US synovitis does not discriminate between sSS and pSS, demonstration of bone erosions in the 2nd MCP joints showed 28.8% sensitivity and 100% specificity for diagnosing sSS; in comparison, these figures were 72.2 and 94.1% for circulating anti-CCP antibodies. Conclusions. In pSS, the pattern of joint involvement by US is polyarticular, bilateral, and symmetrical. Synovitis is the US sign most commonly found in patients with pSS, especially in MCP joints, wrists, and knees, and bone erosions also may occur.

Occurrence of rheumatoid arthritis requiring oral and/or biological disease-modifying antirheumatic drug therapy following a diagnosis of primary Sjögren syndrome

We report 6 patients with an established diagnosis of primary Sjögren syndrome who developed severe rheumatoid arthritis (RA) requiring oral disease-modifying antirheumatic drug with or without biologic therapy. Rheumatoid arthritis was diagnosed between 14 months and 17 years following initial sicca symptoms. Five patients were female. Two thirds were seropositive for Sjögren antibody, and 5 of 6 were either rheumatoid factor or anti-cyclic citrullinated peptide positive at the time of RA diagnosis. All had either hand or wrist involvement; one third had nodules. Although none demonstrated erosion on x-ray, all required methotrexate or leflunomide, and 4 required a biologic agent for the treatment of their arthritis. Primary Sjögren patients may develop RA after a long course of stable Sjögren.

Higher levels of autoantibodies targeting mutated citrullinated vimentin in patients with psoriatic arthritis than in patients with psoriasis vulgaris

Antibodies against citrullinated proteins/peptides (ACPAs), and especially antibodies targeting mutated citrullinated vimentin (anti-MCVs), are novel biomarkers of rheumatoid arthritis (RA). Whereas ACPAs are specific and sensitive markers for RA, there have hardly been any reports relating to ACPAs in psoriatic arthritis (PsA) or in psoriasis without joint symptoms (PsO). The aim of the present study was to investigate the prevalence of anti-MCVs in PsA and PsO. Serum anti-MCV titers were measured in 46 PsA and 42 PsO patients and in 40 healthy controls by means of a commercial enzyme-linked immunosorbent assay. The potential correlations of the serum autoantibody levels with several clinical and laboratory parameters were examined. The anti-MCV levels in the PsA patients were significantly higher than those in the PsO group. Among the clinical variables, the presence of tender knee joints and nail psoriasis was significantly associated with anti-MCV positivity in the PsA patients. Higher anti-MCV titers in the PsO patients were associated with a more severe disease course and with the early onset of psoriatic skin symptoms. Our results suggest that anti-MCVs can be used as novel markers in the diagnosis of PsA and in a subset of PsO patients.

Posttranslational Protein Modification in the Salivary Glands of Sjögren's Syndrome Patients

The present study investigated posttranslational reactions in the salivary glands of patients with Sjögren's syndrome. We analysed the biopsies of primary Sjögren's patients using immunohistochemistry and a tag-purified anticyclic citrullinated protein (CCP) antibody to detect citrullinated peptides, and the presence of peptidylarginine deiminase 2 (PAD2) was assessed simultaneously. The present work demonstrated the weak presence of the PAD2 enzyme in some normal salivary glands, although PAD2 expression was increased considerably in Sjögren's patients. The presence of citrullinated proteins was also detected in the salivary tissues of Sjögren's patients, which strongly supports the in situ posttranslational modification of proteins in this setting. Furthermore, the mutual expression of CCP and PAD2 suggests that this posttranslational modification is enzyme dependent. In conclusion, patients with Sjögren's syndrome expressed the catalytic machinery to produce posttranslational reactions that may result in autoantigen triggering.

Effect of Porphyromonas gingivalis on citrullination of proteins by macrophages in vitro

BACKGROUND

Citrullination of proteins within inflamed periodontal tissues may provide an important link between periodontitis and rheumatoid arthritis. The aim of this study is to determine whether the presence of Porphyromonas gingivalis peptidylarginine deiminase (PPAD) can influence citrullination of proteins by either increasing the amount of local citrullinated protein or influencing the peptidylarginine deiminase (PAD) enzymes found in the monocyte/macrophage population.

METHODS

Human peripheral blood monocytes and macrophages were incubated in the presence of live or heat-killed P. gingivalis. Expression of PAD2 and PAD4, PPAD, and citrullinated proteins were assessed by either a combination of real-time polymerase chain reaction, Western blotting, or a colorimetric assay.

RESULTS

PPAD was detected only in mononuclear cells incubated in the presence of live P. gingivalis and resulted in increased extracellular citrullination. Endogenous PAD (mRNA and protein) expression was detected in monocytes and macrophages but was not affected by P. gingivalis.

CONCLUSION

Although P. gingivalis produces a PAD that can citrullinate extracellular proteins and may contribute to the citrullinated protein load in gingival tissues, it does not appear to affect PAD expression or citrullination by host monocytes or macrophages.

Expression of peptidylarginine deiminase-2 and -4, citrullinated proteins and anti-citrullinated protein antibodies in human gingiva

BACKGROUND AND OBJECTIVE

The presence of citrullinated proteins, and peptidylarginine deiminase types -2 (PAD-2) and -4 (PAD-4) in periodontal tissues, determine the presence of anti-cyclic citrullinated protein antibodies (anti-CCP) in gingival crevicular fluid (GCF) and compare the expression of these proteins between inflamed and non-inflamed sites.

MATERIAL AND METHODS

Tissue sections were stained using antibodies against citrullinated proteins, PAD-2 and PAD-4. RT-PCR was performed to investigate PAD-2 and PAD-4 mRNA in inflamed and non-inflamed gingival tissues. Anti-CCP antibodies in gingival crevicular fluid were detected by ELISA.

RESULTS

Citrullinated proteins, PAD-2 and PAD-4 were detected in gingiva. There was a correlation between inflammation and expression of these proteins. mRNAs for PAD-2 and PAD-4 were detected in both inflamed and non-inflamed gingival tissues. Antibodies to CCP were found mostly in the GCF of individuals with periodontitis.

CONCLUSION

PAD-2 and PAD-4 (protein and mRNA) as well as citrullinated proteins are present in inflamed gingiva, and anti-CCP antibodies can be detected in the GCF of some patients. Tissue expression of citrullinated proteins and PAD increased with the severity of inflammation. The presence of anti-CCP antibodies in GCF was almost exclusive to a subset of patients with periodontitis. Increased expression of these proteins in inflamed gingiva lends support to the notion that periodontal inflammation contributes to the inflammatory burden in a similar way to rheumatoid arthritis.