Anti-cyclic citrullinated peptide antibodies in primary Sjögren syndrome may be associated with non-erosive synovitis

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.

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.

Anti-Citrullinated Peptide Antibody Expression and Its Association with Clinical Features and Outcomes in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Background and objectives: Anti-citrullinated peptide antibody (ACPA), a characteristic antibody detected in rheumatoid arthritis, could be linked to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) via the formation of neutrophil extracellular traps. We investigated the rate of ACPA positivity in patients with AAV and evaluated the association of ACPAs with their clinical features and outcomes. Materials and Methods: A total of 168 AAV patients with both ACPA and ANCA results at diagnosis were identified. Clinical and laboratory variables, including the disease-specific indices of Birmingham Vasculitis Activity Score (BVAS) and Five-Factor Score (FFS), were investigated. All-cause mortality, relapse, and end-stage renal disease, as well as interstitial lung disease (ILD) were evaluated as outcomes of the patients, and the Kaplan–Meier survival analysis was used to compare the event-free survival rates of the groups. Results: Fifteen (8.9%) and 135 (80.4%) patients were positive for ACPA and ANCA, respectively. There were no significant differences in the baseline variables of ACPA-negative and ACPA-positive patients. The absolute titre of ACPAs also did not significantly correlate with BVAS, FFS, erythrocyte sedimentation rate, or C-reactive protein. In addition, there was no difference noted regarding overall, relapse-free, and ESRD-free survival rates between ACPA-negative and ACPA-positive AAV patients. However, when the patients were divided into four groups according to ACPA and ANCA status, differences were present in the outcomes, and the ACPA-positive ANCA-positive group exhibited the lowest cumulative relapse-free survival rate, while no significant difference was present in the relapse between the ANCA-positive ANCA-positive, ACPA-positive ANCA-negative, and ACPA-negative ANCA-positive groups. Finally, the cumulative ILD-free survival rates were comparable between ACPA-positive and ACPA-negative AAV patients. Conclusions: The detection of ACPA expression is not uncommon in AAV. However, the presence of ACPA did not influence patients’ basal characteristics and outcomes, suggesting that further exploration of the role of this antibody is needed in patients with AAV.

The role of albumin-to-globulin ratio in undifferentiated arthritis: Rheumatoid arthritis versus primary Sjögren syndrome

Objectives

This study aims to compare initial albumin-to-globulin ratio (AGR) in patients with rheumatoid arthritis (RA) and primary Sjögren syndrome (pSS) presenting with undifferentiated arthritis (UA) and to investigate whether there was a difference in terms of AGR between the two patient groups and healthy controls.

Patients and methods

Between January 2019 and December 2019, a total of 177 patients including 96 RA (10 males, 86 females; mean age: 53.6±10.8 years; range, 21 to 74 years) and 81 pSS (5 males, 76 females; mean age: 53.2±14.1 years; range, 23 to 79 years) and 82 healthy controls (20 males, 62 females; mean age: 50.5±13.6 years; range, 20 to 79 years) were included in this case-control study. Demographic characteristics, albumin, and globulin levels of all participants were recorded. The AGR, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-nuclear antibody (ANA), and anti-citrullinated protein antibodies (ACPA) were assessed.

Results

The mean AGR was 1.50±0.16 in the control group, 1.48±0.24 in the RA group, and 1.30±0.23 in the pSS group, indicating a significant difference between the pSS and the other two groups (p<0.001). The receiver operating characteristic analysis revealed that the cut-off value for AGR was 1.39 (area under the curve=0.736) with a sensitivity of 0.642 and a specificity of 0.646 (p<0.001). The ESR and CRP values were higher (p<0.001), and ANA (p<0.001) and RF (p=0.003) positivity were lower in the RA group, compared to the pSS group.

Conclusion

This study findings indicate that AGR is a helpful tool in the differential diagnosis of RA and pSS presenting with UA at the time of admission, and Sjögren syndrome should be considered in case of AGR ≤1.39.

Advances in the diagnosis of autoimmune diseases based on citrullinated peptides/proteins

Introduction: Autoimmune diseases are still one of the hard obstacles associated with humanity. There are many exogenous and endogenous etiological factors behind autoimmune diseases, which may be combined or dispersed to stimulate the autoimmune responses. Protein citrullination represents one of these factors. Harnessing specific citrullinated proteins/peptides could early predict and/or diagnose some of the autoimmune diseases. Many generations of diagnostic tools based on citrullinated peptides with comparable specificity/sensitivity are available worldwide.Areas covered: In this review, we discuss the deimination reaction behind the citrullination of most known autoantigens targeted, different generations of diagnostic tools based on citrullinated probes with specificity/sensitivity of each as well as newly developed assays. Furthermore, the most advanced molecular analytical tools to detect the citrullinated residues in the biological fluid and their performance are also evaluated, providing new avenues to early detect autoimmune diseases with high accuracy.Expert opinion: With the current specificity/sensitivity tools available for autoimmune disease detection, emphasis must be placed on developing more advance and effective, early, rapid, and simple diagnostic devices for autoimmune disease monitoring (similar to a portable device for sugar test at home). The molecular analytical devices with dual and/or multiplexe functions should be more simplified and invested in clinical laboratories.

Musculoskeletal Manifestations in Sjogren's Syndrome: An Orthopedic Point of View

Sjogren's syndrome (SS) is a frequent entity with a broad symptomatology spectrum, mainly affecting the salivary and lachrymal glands. The disease also affects the musculoskeletal system targeting bones, specific joints, muscles, and the peripheral nerve system. Disease related clinical manifestations canhave an accumulative impact, as the syndrome is commonly associated with other rheumatic diseases. A literature review was performed with the aim to assess the in-depth association of Sjogren's syndrome and its treatment agents with the musculoskeletal system and further investigate its potential relevance with common orthopedic postoperative complications.

Clinical and laboratory features of patients with focal lymphocytic sialadenitis on minor salivary gland biopsy for sicca symptoms: A single-center experience

Minor salivary gland biopsy (MSGB) is often used in patients lacking specific autoantibodies (seronegative patients) to confirm the presence of focal lymphocytic sialadenitis (FLS), which would suggest a diagnosis of Sjogren syndrome. There are no current guidelines indicating when to refer patients for MSGB. The objective of our study was to ascertain distinguishing clinical and laboratory features among individuals with sicca symptoms based on their serologic and histopathologic status, and to identify factors associated with FLS.Using a cross-sectional study design, patients ages 18 years or older with sicca symptoms who had MSGB performed at the University of Iowa from January 2000 to December 2016 were selected for chart reviews. The clinical and laboratory features of patients with and without FLS were analyzed using exact univariate and multivariable logistic regression, with Bonferroni correction for multiple comparisons.We identified 177 patients who had MSGB performed and available clinical data. A total of 133 patients had FLS, 37 (27.8%) were seropositive (positive-anti-Sjogren syndrome type A [SSA] and/or anti-Sjogren syndrome type B) and 96 (72.2%) were seronegative. Dry eyes (unadjusted odds ratio [OR]: 5.17, 95% confidence interval [CI]: 1.16-26.30; adjusted odds ratio [aOR]: 12.58, 95% CI: 1.70-167.77) and the presence of anti-SSA (OR: 7.16, 95% CI: 1.70-64.24; aOR: 8.82, 95% CI: 1.73-93.93) were associated with FLS. Smoking (aOR 0.27, 95% CI: 0.11-0.63) and antihistamine use (aOR 0.23, 95% CI: 0.08-0.63) were associated with lower odds of FLS.Our study suggests that dry eyes and anti-SSA positivity are associated with FLS. Smoking and antihistamine use were associated with lower odds of FLS. In the appropriate clinical context, seronegative patients with sicca symptoms and no smoking history could be considered for MSGB. A thorough medication and smoking history should be performed in all patients before referral for MSGB.

Barriers to translational research in Sjögren's syndrome with childhood onset: challenges of recognising and diagnosing an orphan rheumatic disease

Sjögren's syndrome was considered for many years a disease of adulthood, characterised by immune infiltration of exocrine glands, leading to dryness (eg, dry mouth and eyes), which is a cardinal symptom. As of the last 20 years, it became apparent that although the disease is very rare in children, its clinical presentation differs from that of adults, posing substantial challenges to the recognition, diagnosis, and classification of patients with childhood-onset Sjögren's syndrome. This Viewpoint explores comparative classification criteria for children (not validated) and adults with Sjögren's syndrome, as well as differences in the clinical presentation of childhood-onset versus adult-onset Sjögren's syndrome, offering ideas about how we can improve the diagnosis of Sjögren's syndrome in children. A review of the role of medical history and clinical assessment, serology, glandular function assessment, and imaging, as well as salivary and lachrymal gland biopsy in the diagnosis of children with Sjögren's syndrome is included. Additionally, we provide suggestions about further research and registry data collection that is required to address the unmet needs of these patients.

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 and diagnostic significance of serum immunoglobulin A rheumatoid factor in primary Sjogren's syndrome

OBJECTIVES

The aim of this study was to investigate the diagnostic accuracy of rheumatoid factor (RF) isotype for the detection of primary Sjogren's syndrome (pSS) and evaluate the clinical and serological associations of immunoglobulin (Ig) A RF in patients with pSS.

MATERIALS AND METHODS

RF levels were measured in 77 and 37 patients with pSS and idiopathic sicca symptoms, respectively, using ELISA and analysed with respect to clinical and laboratory disease characteristics. Receiver operating characteristic curves were used to determine and compare the diagnostic accuracy of IgA RF with other diagnostic tests.

RESULTS

Serum levels of IgA RF were significantly higher in patients with pSS than in those with idiopathic sicca symptoms. IgA RF showed sensitivity, specificity, positive, and negative predictive values of 83.1, 78.4, 88.9, and 69.0%, respectively, for pSS diagnosis. IgA RF was associated with xerostomia, severe sialoscintigraphic grade, low unstimulated salivary flow rate (USFR), antinuclear antibody, high IgG and IgM/G RF levels, and low C3 levels in patients with pSS. IgA RF titres had positive correlations with sialoscintigraphic grade and IgG and IgG/M RF levels and had negative correlations with USFR and C3 levels.

CONCLUSION

Our findings confirmed the potential of IgA RF to distinguish pSS from idiopathic sicca symptoms. The presence of IgA RF in patients with pSS was associated with significantly worse exocrine function and active serologic profile. No association between IgA RF and extra-glandular manifestations was noted.

CLINICAL RELEVANCE

IgA RF should be the predictive and diagnostic marker in patients with pSS.

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.

The prevalence of ANA antibodies, anticentromere antibodies, and anti-cyclic citrullinated peptide antibodies in patients with primary Sjögren's syndrome compared to patients with dryness symptoms without primary Sjögren's syndrome confirmation

Objectives

Our study analyses the prevalence of ANA, anti-SS-A, anti-SS-B, and ACA and ACPA antibodies in patients with pSS and with dryness symptoms without pSS confirmation, and the association of ACPA and ACA antibodies with specific clinical symptoms.

Materials and methods

113 patients were divided into two groups: I – with diagnosed pSS (N = 75); and II – with dryness without pSS evidence (N = 38). Diagnostics: indirect immunofluorescence (IF; Hep-2 cell line) of antinuclear antibodies (ANA), anti-SS-A anti-SS-B antibodies determined with semi-quantitative method, autoantibody profile (14 antigens, ANA Profil 3 EUROLINE); basic laboratory, ophthalmic examination tests, minor salivary gland biopsy with focus score (FS), joint and lung evaluation, and ESSDAI questionnaire (pSS activity).

Results

88% of group I had ANA antibodies (1 : 320 titre), 5.3% at 1 : 160. Anti-SS-A antibodies were present in 88% of group I, including all ANA 1 : 160. Anti-SS-A antibodies positively correlated with greater and moderate activity of ESSDAI 5 (p = 0.046) and FS. The presence of SS-B antibodies significantly affected disease activity. ACPA present: group I – 13% (associated with higher arthritis incidence; p = 0.003); group II – 8%. ACA antibodies present in 4% of group I, but not in group II. No ACA association with interstitial lung changes (small ACA + group excludes full conclusions).

Conclusions

ANA antibodies should also be considered in a titre of less than 1 : 320, but the presence of anti-SS-A antibodies is still the most important immunological marker for pSS. Anti-SS-A antibodies correlate with higher disease activity (ESSDAI ≥ 5) and higher FS. The presence of the anti-SS-B antibody was significantly affected by higher activity of the disease. The incidence of arthritis was higher in patients with ACPA+ pSS compared to ACPA– (p = 0.003). There was no relationship between ACPA and arthritis in patients with dry-type syndrome without diagnosis of pSS.

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).

Antibodies against carbamylated proteins are present in primary Sjögren's syndrome and are associated with disease severity

Objectives

Herein, we investigate the presence and prognostic value of autoantibodies against carbamylated proteins (anti-CarP) in the serum of patients with primary Sjögren's syndrome (pSS).

Patients and methods

Serum levels of anti-CarP antibodies were measured in Norwegian patients with pSS (n=78) and corresponding controls (n=74) using ELISA and analysed in relation with exocrine gland function, degree of salivary gland inflammation, signs of ectopic germinal centre (GC) formation and immunological markers. For univariate comparisons, the Mann–Whitney U test and χ² or Fisher's exact tests were used. Correlations were assessed with Spearman's rank testing. Multivariate regression analyses were used to assess the effect of anti-CarP positivity on clinical manifestations.

Results

Of the patients with pSS, 27% were positive for anti-CarP IgG antibodies. Levels of anti-CarP correlated positively with total IgG, IgM, rheumatoid factor and β2-microglobulin. Importantly, after adjusting for confounding factors, patients positive for anti-CarP had significantly higher focus score. Furthermore, positive anti-CarP status coincided with 9.2-fold higher odds of having developed GC-like structures in the minor salivary glands. As a patient group considered having worse disease outcome, individuals with ectopic GC-like structures also presented with significantly higher levels of anti-CarP antibodies.

Conclusions

Presence of anti-CarP in patients with pSS is strongly associated with increased focal lymphocytic infiltration, formation of ectopic GC-like structures in minor salivary glands, and diminished salivary gland function. Even taking into consideration our relatively small cohort we believe that anti-CarP antibodies offer new possibilities for identifying patients with more active disease and at risk of developing additional comorbidity.

Diagnostic performance of anti-cyclic citrullinated peptide and rheumatoid factor in patients with rheumatoid arthritis

AIM

To compare the diagnostic performance of rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-CCP) in the diagnosis of patients with rheumatoid arthritis (RA) in Taiwan.

METHODS

Serum concentrations of RF and anti-CCP were measured in 246 cases, including 39 patients with RA and 207 patients with other rheumatic diseases (non-RA). The age, sex, clinical presentation, RF, anti-CCP results and the final diagnoses were recorded and analyzed. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+) and negative likelihood ratio (LR-) were calculated.

RESULTS

Among all 246 patients, 39 (15.9%) were diagnosed with RA and 207 (84.1%) were diagnosed with other rheumatic diseases (non-RA). In the diagnosis of RA, the sensitivity, specificity, PPV, NPV, LR+ and LR- of the RF test were 67%, 79%, 37%, 93%, 3.12, and 0.42, respectively. The corresponding data for the anti-CCP test were 79%, 98%, 86%, 96%, 32.91 and 0.21, respectively. The presence of either anti-CCP or RF increased the sensitivity to 85%, and when they both were present, the specificity increased to 98%. Among the 39 RA patients, 26 (66.7%) tested positive for RF, and 31 (79.5%) tested positive for anti-CCP. RF was positive in two of eight anti-CCP-negative patients with RA, and anti-CCP was positive in seven of 13 RF-negative patients with RA.

CONCLUSIONS

The RF and anti-CCP tests are complementary, and the co-detection of these antibodies can increase the detection rate and provide important clinical value in the diagnosis of RA. Both anti-CCP and RF positivity are useful for the diagnosis of RA, and use of both tests together improves the diagnostic sensitivity.

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.

Significant association of periodontal disease with anti-citrullinated peptide antibody in a Japanese healthy population - The Nagahama study

Anti-citrullinated peptide antibody (ACPA) is a highly specific autoantibody to rheumatoid arthritis (RA). Recent studies have revealed that periodontal disease (PD) is closely associated with RA and production of ACPA in RA. Analyses of associations between PD and ACPA production in a healthy population may deepen our understandings. Here, we analyzed a total of 9554 adult healthy subjects. ACPA and IgM-rheumatoid factor (RF) was quantified and PD status was evaluated using the number of missing teeth (MT), the Community Periodontal Index (CPI) and Loss of Attachment (LA) for these subjects. PD status was analyzed for its association with the positivity and categorical levels of ACPA and RF conditioned for covariates which were shown to be associated with PD, ACPA or RF. As a result, all of MT, CPI and LA showed suggestive or significant associations with positivity (p = 0.024, 0.0042 and 0.037, respectively) and levels of ACPA (p ≤ 0.00031), but none of the PD parameters were associated with those of RF. These association patterns were also observed when we analyzed 6206 non-smokers of the participants. The significant associations between PD parameters and positivity and levels of ACPA in healthy population support the fundamental involvement of PD with ACPA production.

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.

The epidemiology of Sjögren's syndrome

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

Sjögren's syndrome: still not fully understood disease

Primary Sjögren's syndrome is an autoimmune disorder with external exocrine glands dysfunction and multiorgan involvement. The pathogenesis of primary Sjogren’s syndrome is still unclear; however, our knowledge of the involvement of different cells (e.g., B and T cells, macrophages and dendritic cells) and pathways (BAFF/APRIL and interferons) leading to the development of autoimmunity is continually expanding. For clinicians, the most frequent symptoms are dryness of eyes and mouth, but often the patients have musculoskeletal symptoms and systemic manifestations. However, the increased risk of lymphoproliferative disorders in this group of patients, most commonly B-cell marginal zone lymphoma, is particularly important. Recent separation of IgG4-related diseases and attempts to create further diagnostic criteria for pSS testify to the difficulties, and at the same time a large interest, in understanding the disease so as to allow the effective treatment. This article draws attention to the problems faced by the clinician wishing to securely identify pSS by using accurate laboratory biomarkers and useful imaging tools and predict the development of complications associated with this, still not fully understood, autoimmune disease.

Th1 and Th2 polymorphisms in Sjögren's syndrome and rheumatoid arthritis

BACKGROUND

Sjogren's syndrome is characterized by T-cell infiltration of exocrine glands leading to parenchymal destruction and impaired glandular function. This process is orchestrated by cytokines, whose secretion can be regulated by genetic polymorphisms.

MATERIALS AND METHODS

The aim of this study was to investigate the influence of interleukin-6 -174G/C, interleukin-10 -1082G/A, tumor necrosis factor-α -308G/A, interferon-γ +874A/T gene polymorphisms in (RA) and secondary Sjögren's syndrome (sSS). A study sample that comprised of 138 Brazilian patients was divided into three groups: RA (n = 66), sSS (n = 20), and healthy controls - C (n = 52). Patients were subjected to Schirmer's test, unstimulated salivary flow rate, biopsy of minor salivary glands, and serological tests for diagnosing SS. Genomic DNA was obtained from saliva samples and submitted to genotyping. The association between genotypes/alelle frequency and SS susceptibility was tested, as well as their association with clinical features of SS.

RESULTS

Tumor necrosis factorα (TNFα)-308GA polymorphisms differed significantly between AR, SS, and C patients (P = 0.008). IL-6 overall G carriers and TNFα A carriers had a higher risk of presenting SS (P = 0.021). IL-6 polymorphism distribution was also distinctive regarding lymphocytic infiltration at the minor salivary glands (P = 0.026) and Schirmer's test (P = 0.035).

CONCLUSION

These results suggest that IL-6 -174GC and TNFα-308GA gene polymorphisms are associated with susceptibility to SS. Additionally, IL-6 polymorphism could influence lymphocytic infiltration of salivary glands and diminish lachrymal gland function.

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.

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.

Subgroups of Sjögren syndrome patients according to serological profiles

Sjögren Syndrome (SS) is a systemic, autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands. Different clinical associations have been described for each of the diverse autoantibodies found in SS patients. Antibodies directed against the Ro/La ribonucleoprotein complexes have been correlated with younger age, more severe dysfunction of the exocrine glands and a higher prevalence of extraglandular manifestations. Anti-nuclear antibodies and rheumatoid factors have been associated to extraglandular manifestations and an active immunological profile, while cryoglobulins are markers of more severe disease and correlate to lymphoma development and death. Antibodies to cyclic citrullinated peptides are scarce in SS and have been linked in some cases to the development of non-erosive arthritis. Furthermore, the presence of anti-mitochondrial antibodies and anti-smooth muscle antibodies in the sera of primary SS patients is considered indicative of primary biliary cirrhosis and autoimmune hepatitis, respectively. In addition, anti-centromere antibodies have been associated with a clinical phenotype intermediate between primary SS and systemic sclerosis, while antibodies against carbonic anhydrase have been related to renal tubular acidosis. Finally, an association of anti-muscarinic antibodies with cytopenias and a higher disease activity has also been described in primary SS. In conclusion, although not all of the above mentioned antibodies are useful for predicting distinct patient subgroups in SS, knowledge of the clinical associations of the different autoantibody specificities encountered in SS can advance our understanding of the disease and improve patient management.

Autoantibodies in Sjögren's syndrome: clinical presentation and regulatory mechanisms

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease mostly affecting the exocrine glands. A large number of autoantibodies have been detected in the serum of patients with pSS. Among them, anti-Ro/SSA and anti-La/SSB autoantibodies are the most common; they serve as disease markers and are involved in the pathogenesis of neonatal lupus syndrome (NLS). Other autoantibodies are associated with significant clinical phenotypes, such as cryoglobulins with development of non-Hodgkin's lymphoma, anti-centromere antibodies with Raynaud's phenomenon and anti-mitochondrial antibodies with liver pathology. As a result, pSS patients can be schematically categorized in subgroups according to their serological profile. Although the clinical utility of these autoantibodies is appreciated, little is known about the mechanisms related to their production and the regulation of the autoimmune response. In the present review, the clinical subsets of patients with pSS related to different autoantibodies as well as the regulating mechanisms of their production with special emphasis on idiotypic/anti-idiotypic network are discussed.

Subclinical synovitis in primary Sjögren's syndrome: an ultrasonographic study

OBJECTIVES

To evaluate, by musculoskeletal ultrasound (MSUS), articular involvement in primary SS (pSS) patients by analysing hand and wrist changes, and to correlate them with clinical evaluation and laboratory tests.

METHODS

Thirty-two pSS patients underwent clinical and laboratory examinations, including the SS Disease Damage Index (SSDDI) and the SS Disease Activity Index (SSDAI). MSUS was performed in all patients in both hands and wrists, evaluating the presence of inflammation within joints and periarticular tissues, and the existence of permanent joint damage. For synovial hypertrophy, joint effusion and Doppler signal findings, a semi-quantitative score (0-3) was used indicating the degree of involvement (0 = normal; 1 = mild change; 2 = moderate change; and 3 = severe change). For tenosynovitis and bone erosions, a dichotomous score (0 = absent and 1 = present) was applied.

RESULTS

Sonographic signs of synovitis of the radio-ulno-carpal joint were found in 17 (26.5%) out of 64 wrists. Wrist synovitis was found in 12 (37.5%) out of 32 patients. Ultrasonographic examination of the hand did not show significant changes. A statistically significant correlation was found between SSDDI score and the degree of sonographic signs of synovial proliferation in the wrist (P = 0.04). The correlation between the incidence of clinical involvement and the presence of pathological ultrasonographic findings was not significant. Patients with synovitis had a higher median age and higher median SSDDI (P = 0.004).

CONCLUSIONS

In pSS patients, MSUS may be considered a useful tool for detecting synovitis since articular involvement can often be silent but correlated with SSDDI.

Rheumatoid arthritis and smoking: putting the pieces together

Besides atherosclerosis and lung cancer, smoking is considered to play a major role in the pathogenesis of autoimmune diseases. It has long been known that there is a connection between rheumatoid factor-positive rheumatoid arthritis and cigarette smoking. Recently, an important gene-environment interaction has been revealed; that is, carrying specific HLA-DRB1 alleles encoding the shared epitope and smoking establish a significant risk for anti-citrullinated protein antibody-positive rheumatoid arthritis. We summarize how smoking-related alteration of the cytokine balance, the increased risk of infections (the possibility of cross-reactivity) and modifications of autoantigens by citrullination may contribute to the development of rheumatoid arthritis.