Anti-cyclic citrullinated peptide antibodies in scleroderma patients

Systemic Sclerosis Sine Scleroderma: A Time of Reappraisal

OBJECTIVE

Systemic sclerosis sine scleroderma (ssSSc), formally described in 1962, is a subset of SSc that, unlike limited cutaneous (lcSSc) and diffuse cutaneous (dcSSc) forms, lacks skin fibrosis. According to the 2013 American College of Rheumatology/European Alliance of Associations for Rheumatology criteria, SSc can be diagnosed in the absence of skin thickening, even if this is expected to develop later in disease course. Driven by a fatal case of ssSSc with cardiac involvement, we analyzed published data on ssSSc prevalence and severity.

METHODS

A systematic literature review and qualitative synthesis of SSc cohorts with data on ssSSc were performed.

RESULTS

Thirty-five studies involving a total of 25,455 patients with SSc, published between 1976 and 2023, were identified. Although different definitions were used, the mean prevalence of ssSSc was almost 10% (range 0-23%), with the largest study reporting a cross-sectional prevalence of 13%. In 5 studies with a follow-up period of up to 9 years, reclassification of ssSSc into lcSSc or dcSSc ranged 0-28%. Interstitial lung disease, pulmonary arterial hypertension, scleroderma renal crisis, and cardiac diastolic dysfunction were present in 46% (range 9.3-59.1%), 15% (range 5.9-24.6%), 5% (range 1.6-24.6%), and 26.5% (range 1.8-40.7), respectively, of patients with ssSSc. Survival across studies was comparable to lcSSc and better than dcSSc.

CONCLUSION

Published data on ssSSc vary widely on prevalence, clinical expression, and prognosis, partly due to underdiagnosis and misclassification. Although classification criteria should not affect appropriate management of patients, updated ssSSc subclassification criteria that takes into account time from disease onset should be considered.

Treatment of Inflammatory Arthritis in Systemic Sclerosis

Joint involvement, including arthralgia, inflammatory arthritis, joint contractures and overlapping with rheumatoid arthritis, is a common manifestation and is associated with impared quality of life in systemic sclerosis (SSc). Few studies have evaluated the treatment of arthritis in SSc. Pharmacological approach includes low-dose corticosteroids, methotrexate, and hydroxychloroquine. Non-tumor necrosis factor biologics, especially rituximab and tocilizumab, may be a promising option for refractory cases.

A retrospective analysis of the relationship between anti-cyclic citrullinated peptide antibody and interstitial lung disease in systemic sclerosis

Anti-cyclic citrullinated peptide antibody testing is used to diagnose rheumatoid arthritis and associated with interstitial lung disease in RA. Herein, we investigate the relationship between anti-CCP antibody and ILD in SSc. We performed a retrospective analysis at a tertiary medical center between 2005 and 2019. Patients with SSc, systemic lupus erythematosus, and polymyositis/dermatomyositis (PM/DM) were evaluated for anti-CCP antibody and ILD. Additionally, medical records of SSc patients with ILD were reviewed. SSc patients had the highest anti-CCP antibody positivity rate compared to those with SLE and PM/DM. The incidence of ILD was higher in SSc patients with anti-CCP antibody than in those without. The usual interstitial pneumonia (UIP) incidence was higher in the anti-CCP antibody-positive group than in the anti-CCP antibody-negative group. The DLCO was lower in the anti-CCP antibody-positive group than in the anti-CCP antibody-negative group. On multivariable analysis, factors associated with SSc-ILD were anti-CCP antibody or rheumatoid factor (β coefficient, 2.652 [95% CI 1.472 to 4.776]) and anti-Scl70 antibody (β coefficient, 4.011 [95% CI 2.142 to 7.508]). Anti-CCP antibody may be associated with a higher incidence of ILD in SSc. SSc patients with anti-CCP antibody may have more UIP pattern and lower DLCO.Trial Registration Retrospectively registered.

Erosive arthritis autoantibodies in systemic sclerosis

OBJECTIVE

We aimed to evaluate in two large SSc French cohorts the prevalence and associated factors with the autoantibodies linked to erosive arthritis.

METHODS

448 SSc patients were recruited from May 2015 to January 2019. Standardized clinical and laboratory variables were collected in accordance with the EUSTAR database. ELISAs for IgM rheumatoid factor (RF), IgG anti-citrullinated proteins (ACPA) and IgG anti-carbamylated proteins antibodies (anti-CarP) were all determined in a central laboratory. The prevalence and clinical associations of the different antibodies were investigated.

RESULTS

RF positivity was observed in 113 patients (25%) compared to 39 (9%) for ACPA and 63 (14%) for anti-CarP antibodies. Through multivariate regression analysis, both RF and ACPA positivity resulted to be associated with RA overlap disease (OR 5.7, 95% CI 2.3-13.8 and OR 44.1, 95% CI 15.4-126.3, respectively). Additionally, ACPA was found to be significantly related to synovitis/ tenosynovitis (OR 1.7, 95% CI 1.0-2.6). RF positivity was associated to a "vascular subset" (i.e. any major vascular complication) (OR 2.1, 95% CI 1.3-3.4). Moreover, anti-CarP antibodies were associated with a fibrotic subset and with digital ulcers (OR 2.0, 95% CI 1.1-3.6 and OR 1.9, 95% CI 1.1-3.4).

CONCLUSION

We corroborated that ACPA could be useful in identifying patients with a more prominent joint disease and RA overlap disease. Of the most interest we found that anti-CarP antibodies could be a relevant biomarker related to fibrotic skin and lung disease.

Prevalence of auto-antibodies associated to pulmonary arterial hypertension in scleroderma - A review

The prevalence of auto-antibodies associated to pulmonary arterial hypertension in scleroderma patients was reviewed, based on reports cited in two major scientific databases. Data were collected on the following types of antibodies: antinuclear, anti-double-stranded DNA, anticentromere, anti-CENP-A, anti-CENP-B, anti-bicaudal D2, anti-nucleolar, anti-Scl-70 (anti-topoisomerase I), anti-topoisomerase II α, anti-RNP, anti-U1RNP, anti-U3RNP, anti-RNA polymerase III, anti-Th/To, anti-histone, antiphospholipid, anti-PmScl, anti-Sm, anti SSA (anti-Ro),anti SSB (La), anti-Ro52 (TRIM 21), anti-Ku, anti-B23, anti-RuvBL1, anti-RuvBL2, anti-fibrin bound tissue plasminogen activator, anti-endothelial cell, anti-phosphatidylserine-prothrombin complex, anti-endothelin-1 type A receptor, anti-angiotensin II type 1 receptor, anti‑carbonic anhydrase II, anti-fibroblast, anti-cyclic citrullinated peptide, anti-4-sulfated N-Acetyl-lactosamine, class I and II anti-human leukocyte antigen. Auto-antibodies were shown by different authors to be associated to this condition, with different prevalence values for each type of auto-antibody. Antinuclear antibodies, anti-centromere antibodies, antiphospholipid antibodies, anti-U3 RNP antibodies and anti-Th/To antibodies would appear to show a particularly important prevalence in scleroderma patients with pulmonary hypertension, appearing in about 8/10 (antinuclear), 1/ 2 (anti-centromere, anti-phospholipid), and 1/4 (anti-U3RNP, anti-Th/To) of patients. The available evidence points in the direction of a strong association between auto-immune mechanisms and pulmonary hypertension in the setting of scleroderma.

Anti-citrullinated peptides antibodies in systemic sclerosis: Meta-analysis of frequency and meaning

OBJECTIVES

Diagnosis of systemic sclerosis (SSc) is partially determined by the presence of specific autoantibodies often associated with specific clinical features. Recent studies report the presence of ACPA in SSc. We aimed to evaluate the prevalence of ACPA in SSc and to assess their influence on clinical presentation of SSc.

METHODS

A systematic literature search was performed using PubMed and Cochrane databases' publications between 1999 and March 2017. Search terms were: "systemic sclerosis [MeSH] AND (ACPA OR anti-CCP OR rheumatoid factor OR cohort OR value diagnostic)". In a first step, we selected cohorts with >50 SSc patients with ACPA identification, for ACPA frequency determination. In a second step, we included studies that analysed clinical profiles according to ACPA status. Meta-analyses were performed when at least two studies were available.

RESULTS

First, we identified 13 observational studies with a total of 1231 SSc patients. The mean prevalence of ACPA in SSc was 9.2%. Secondly, we identified nine studies reporting clinical aspects according to ACPA status. Our meta-analyses showed a significant association between ACPA positivity and the presence of arthritis (odds ratio (OR)=22.48 [10.71-47.21]), joint erosions seen on X-rays (OR=14.79 [6.38-34.28]), pulmonary fibrosis (OR=2.75 [1.21-6.24]), oesophagus involvement (OR=2.72 [1.05-7.07]), and diffuse skin involvement (OR=2.21 [1.21-4.03]).

CONCLUSIONS

The prevalence of ACPA in scleroderma is 9.2%. Our meta-analysis shows an increased risk for erosive arthritis, pulmonary fibrosis, oesophagus involvement and diffuse skin involvement, in patients with ACPA-positive SSc. ACPA should be systematically included in SSc assessment.

Demographic associations for autoantibodies in disease-free individuals of a European population

The presence of autoantibodies usually precedes autoimmune disease, but is sometimes considered an incidental finding with no clinical relevance. The prevalence of immune-mediated diseases was studied in a group of individuals from the Estonian Genome Project (n = 51,862), and 6 clinically significant autoantibodies were detected in a subgroup of 994 (auto)immune-mediated disease-free individuals. The overall prevalence of individuals with immune-mediated diseases in the primary cohort was 30.1%. Similarly, 23.6% of the participants in the disease-free subgroup were seropositive for at least one autoantibody. Several phenotypic parameters were associated with autoantibodies. The results suggest that (i) immune-mediated diseases are diagnosed in nearly one-third of a random European population, (ii) 6 common autoantibodies are detectable in almost one-third of individuals without diagnosed autoimmune diseases, (iii) tissue non-specific autoantibodies, especially at high levels, may reflect preclinical disease in symptom-free individuals, and (iv) the incidental positivity of anti-TPO in men with positive familial anamnesis of maternal autoimmune disease deserves further medical attention. These results encourage physicians to evaluate autoantibodies in addition to treating a variety of patient health complaints to detect autoimmune-mediated disease early.

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-CCP in systemic lupus erythematosus patients: a cross sectional study in Brazilian patients

Recently, it has been found that some lupus patients may have anti-cyclic citrullinated peptide antibodies (anti-CCP), although the clinical significance of such finding is not well established. Systemic lupus erythematosus (SLE) patients may have joint complaints that are very similar to those observed in rheumatoid arthritis (RA). In early stages of disease, this form of arthritis can be difficult to differentiate from RA, so it is not rare that some SLE patients are initially misdiagnosed to have this disease. This study aims to investigate the prevalence of anti-CCP in SLE patients from Southern Brazil and its association with clinical and serological profiles. One hundred nine SLE patients were studied for anti-CCP and compared with data of 156 RA patients and 100 healthy volunteers. Comparison of clinical and autoantibody profile of anti-CCP-positive and anti-CCP-negative SLE patients was done. All SLE patients positive of anti-CCP were submitted to hand and feet X-rays. Anti-CCP was positive in 15 of 109 SLE patients, and one of them had confirmed the diagnosis of rhupus. This prevalence was significantly higher than in healthy controls (p = 0.0004) and lower than in RA patients (p < 0.0001). No relationship could be found with clinical profile, including joint complaints. SLE patients with anti-CCP had higher prevalence of anti-Ro (p = 0.02) and anti-La (p = 0.004) autoantibodies, in comparison with those negative to anti-CCP. We found that 13.7% of Brazilian patients with SLE have positive anti-CCP. Patients with anti-CCP showed higher prevalence of anti-Ro and anti-La autoantibodies than those negative for anti-CCP. Only a careful and prolonged follow-up will reveal the real clinical value of these markers in each patient individually.