Pathogenic role of anti-nuclear autoantibodies in systemic sclerosis: Insights from other rheumatic diseases.

Systemic sclerosis (SSc) is a severe autoimmune disease characterized by vasculopathy, fibrosis, and dysregulated immunity, with hallmark autoantibodies targeting nuclear antigens such as centromere protein (ACA) and topoisomerase I (ATA). These autoantibodies are highly prevalent and disease-specific, rarely coexisting, thus serving as crucial biomarkers for SSc diagnosis. Despite their diagnostic value, their roles in SSc pathogenesis remain unclear. This review summarizes current literature on ACA and ATA in SSc, comparing them to autoantibodies in other rheumatic diseases to elucidate their potential pathogenic roles. Similarities are drawn with anti-citrullinated protein antibodies (ACPA) in rheumatoid arthritis, particularly regarding disease specificity and minimal pathogenic impact of antigen binding. In addition, differences between ANA and ACPA in therapeutic responses and Fab glycosylation patterns are reviewed. While ACA and ATA are valuable for disease stratification and monitoring activity, understanding their origins and the associated B cell responses is critical for advancing therapeutic strategies for SSc.

Circulating levels of endogenous complement inhibitors correlate inversely with complement consumption in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is marked by excessive complement activation, contributing to tissue damage. Complement activation can be detected in many organs including the skin, kidney, and brain. The involvement of the central nervous system is particularly relevant to understanding neuropsychiatric SLE (NPSLE), one of the poorest understood manifestations of SLE for which no biomarkers are available. We studied the levels of complement inhibitors in SLE in relation to disease activity and as possible biomarkers to identify NPSLE. Serum levels of complement inhibitors C1-inhibitor (C1-INH), C4b-binding protein (C4BP), Factor I, and Factor H were measured in 345 SLE patients (including 102 with NPSLE) and 108 healthy controls. Compared with controls, SLE patients had higher C1-INH and C4BP but lower Factor I and H levels. All inhibitors positively correlated with total C3 and C4 levels. While correlating with the SLE Disease Activity Index (SLEDAI), no distinction in inhibitor levels was found between SLE and NPSLE patients. Over time, C1-INH and Factor H levels normalized, but no significant changes were observed for C4BP and Factor I. In SLE the levels of circulating complement inhibitors are inversely correlated to complement consumption but do not serve as biomarkers for NPSLE.

Acetylated bacterial proteins as potent antigens inducing an anti-modified protein antibody response.

OBJECTIVE: Gut-residing bacteria, such as Escherichia coli, can acetylate their proteome under conditions of amine starvation. It is postulated that the (gut) microbiome is involved in the breach of immune tolerance to modified self-proteins leading to the anti-modified protein antibodies (AMPAs), hallmarking seropositive rheumatoid arthritis (RA). Our aim was to determine whether acetylated bacterial proteins can induce AMPA responses cross-reactive to modified self-proteins and be recognised by human AMPA (hAMPA). METHODS: E. coli bacteria were grown under amine starvation to generate endogenously acetylated bacterial proteins. Furthermore, E. coli proteins were acetylated chemically. Recognition of these proteins by hAMPA was analysed by western blotting and ELISA; recognition by B cells carrying a modified protein-reactive B cell receptor (BCR) was analysed by pSyk (Syk phosphorylation) activation assay. C57BL/6 mice were immunised with (modified) bacterial protein fractions, and sera were analysed by ELISA. RESULTS: Chemically modified bacterial protein fractions contained high levels of acetylated proteins and were readily recognised by hAMPA and able to activate B cells carrying modified protein-reactive BCRs. Likely due to substantially lower levels of acetylation, endogenously acetylated protein fractions were not recognised by hAMPA or hAMPA-expressing B cells. Immunising mice with chemically modified protein fractions induced a strong cross-reactive AMPA response, targeting various modified antigens including citrullinated proteins. CONCLUSIONS: Acetylated bacterial proteins are recognisable by hAMPA and are capable of inducing cross-reactive AMPA in mice. These observations provide the first conceptual evidence for a novel mechanism involving the (endogenous) acetylation of the bacterial proteome, allowing a breach of tolerance to modified proteins and the formation of cross-reactive AMPA.

Untangling the relationship between smoking and systemic sclerosis: an analysis of the EUSTAR cohort.

OBJECTIVES: To untangle the association between smoking and systemic sclerosis (SSc). METHODS: In the European Scleroderma Trials and Research cohort, the autoantibody status was compared between ever-smokers and never-smokers. Time until disease progression was assessed using Kaplan-Meier curves. Cox models were built to investigate the influence of smoking over 15 years of follow-up. All analyses were performed for the total cohort and stratified for sex and for positivity of anti-centromere (ACA) and anti-topoisomerase antibodies (ATA). RESULTS: Overall, 12 314 patients were included in the study. Of these, 10 393 were women (84%), 4637 were ACA-positive (38%), 3919 were ATA-positive (32%) and 4271 (35%) were ever-smokers. In men, but not in women, smoking was associated with mortality (HR 1.63, 95% CI 1.23 to 2.16, p=0.001). Ever-smoking women were at higher risk for skin progression (HR 1.10, 95% CI 1.00 to 1.22, p=0.046) and for 'any organ progression' (HR 1.07, 95% CI 1.00 to 1.13, p=0.036). In women, 34% of never-smokers were ATA-positive compared with 21% of ever-smokers (p<0.001). In the group of ever-smokers, higher exposure rates, reflected by the number of pack-years (OR 0.98, 95% CI 0.97 to 0.99, p<0.001) and by smoking duration (OR 0.96, 95% CI 0.95 to 0.97, p<0.001), were associated with lower frequency of ATA. In ACA-positive patients, the risk of mortality (HR 1.29, 95% CI 1.02 to 1.63, p=0.033), cardiac involvement (HR 1.25, 95% CI 1.03 to 1.43, p=0.001), skin progression (HR 1.21, 95% CI 1.03 to 1.42, p=0.018) and 'any organ progression' (HR 1.14, 95% CI 1.05 to 1.24, p=0.002) was increased among smokers. In ATA-positive smoking patients, mortality (HR 1.40, 95% CI 1.10 to 1.78, p=0.006), skin progression (HR 1.19, 95% CI 1.03 to 1.37, p=0.020) digital ulcers (HR 1.17, 95% CI 1.02 to 1.34, p=0.029) and 'any organ progression' (HR 1.11, 95% CI 1.00 to 1.22, p=0.048) occurred more frequently. CONCLUSIONS: Our stratified analysis demonstrates that smoking is associated with an increased risk for mortality in male SSc patients but not in women. Strikingly, smoking is associated with lower prevalence of ATA positivity, in particular in women. In both ATA-positive and ACA-positive patients, smoking is a risk factor for mortality, skin progression and 'any organ progression'.

Long-term clinical outcomes in early rheumatoid arthritis that was treated-to-target in the BeSt and IMPROVED studies.

OBJECTIVES: To assess disease outcomes after 20 and 12 years of patients with rheumatoid (RA) or undifferentiated arthritis (UA), treated-to-target in the BeSt and IMPROVED trials. METHODS: In BeSt (inclusion 2000-2002, duration 10 years), 508 patients with early RA were randomized to: 1. sequential monotherapy, 2. step-up combination therapy, 3. initial csDMARD combination therapy, 4. initial bDMARD/csDMARD combination therapy. The treatment target was low disease activity (DAS ≤ 2.4).In IMPROVED (inclusion 2007-2010, duration 5 years), 610 patients with early RA/UA started MTX with prednisone bridging. The treatment target was remission (DAS < 1.6). Patients not in early remission were randomized to 1. csDMARD combination therapy or 2. bDMARD/csDMARD combination therapy.Between 2019-2022, these patients were invited for long-term follow-up. RESULTS: One-hundred-fifty-three ex-Best and 282 ex-IMPROVED patients participated in the follow-up study after median 12 and 20 years since study start.In ex-BeSt and ex-IMPROVED patients the rate of low disease activity was 91%, and 68% were in DAS remission. Median SHS was 14.0 in ex-BeSt (IQR 6.0-32.5; progression since end BeSt 6.0, IQR 2.0-12.5) and 8 in ex-IMPROVED participants (IQR 3-16; progression since end IMPROVED 4, IQR 2-9). Mean HAQ was 0.8 ± 0.6 in ex-BeSt (change since end BeSt: 0.3 ± 0.5) and 0.6 ± 0.6 in ex-IMPROVED participants (change since end IMPROVED: 0.06 ± 0.5). CONCLUSION: At 12/20 years after treatment start, the majority of RA and UA patients who had been treated to target low DAS or DAS remission were in DAS remission and had limited functional disability. Radiographic damage progression was mild although not completely suppressed.

Prednisone use, disease activity and the occurrence of hyperglycaemia and diabetes in patients with early rheumatoid arthritis: a 10-year subanalysis of the BeSt study.

OBJECTIVES: To assess whether prednisone use and/or disease activity score (DAS) are associated with the development of hyperglycaemia and diabetes in rheumatoid arthritis (RA). METHODS: We included 504 non-diabetic early RA patients from the BeSt study (Dutch acronym for treatment strategies). Patients were randomised to four DAS-steered treatment arms and followed for 10 years. The associations between DAS and prednisone use with glucose levels and the occurrence of hyperglycaemia over time were assessed with linear and logistic mixed effects regression models. Development of diabetes was analysed with Cox regression. Sensitivity analyses were performed in patients who had a first episode of hyperglycaemia. RESULTS: 31 of 504 patients (6.2%) with a mean age of 54 years developed diabetes during follow-up; 11 of these (35%) had received prior treatment with prednisone. Prednisone use was not associated with development of hyperglycaemia or diabetes after correction for multiple testing in main or sensitivity analyses. In the main analyses, DAS was significantly associated with development of diabetes (HR 1.802 per 1 point DAS increase, 95% CI 1.284 to 2.529) but not with glucose levels nor hyperglycaemia. In patients with previous hyperglycaemia, DAS was associated with glucose levels, recurrence of hyperglycaemia and diabetes. CONCLUSIONS: In non-diabetic early RA patients, the use of prednisone was not associated with developing hyperglycaemia or diabetes. However, high DAS increased the risk of diabetes. Potential risks associated with prednisone use may have been mitigated by its effect on DAS.

Antigen-specific Fab profiling achieves molecular-resolution analysis of human autoantibody repertoires in rheumatoid arthritis.

The presence of autoantibodies is a defining feature of many autoimmune diseases. The number of unique autoantibody clones is conceivably limited by immune tolerance mechanisms, but unknown due to limitations of the currently applied technologies. Here, we introduce an autoantigen-specific liquid chromatography-mass spectrometry-based IgG1 Fab profiling approach using the anti-citrullinated protein antibody (ACPA) repertoire in rheumatoid arthritis (RA) as an example. We show that each patient harbors a unique and diverse ACPA IgG1 repertoire dominated by only a few antibody clones. In contrast to the total plasma IgG1 antibody repertoire, the ACPA IgG1 sub-repertoire is characterised by an expansion of antibodies that harbor one, two or even more Fab glycans, and different glycovariants of the same clone can be detected. Together, our data indicate that the autoantibody response in a prominent human autoimmune disease is complex, unique to each patient and dominated by a relatively low number of clones.

Risk Factors for Antiphospholipid Antibodies and Antiphospholipid Syndrome.

Persistence of serum antiphospholipid antibodies (aPL) is associated with a high thrombotic risk, both arterial and venous, and with pregnancy complications. Due to the potential morbidity and mortality associated with the presence of aPL, identifying and recognizing risk factors for the development of aPL and thrombosis in aPL carriers may help to prevent and reduce the burden of disease. Multiple elements are involved in the pathomechanism of aPL development and aPL-related thrombosis such as genetics, malignancy, and infections. This review will address the role of both well-known risk factors and their evolution, and of emerging risk factors, including COVID-19, in the development of aPL and thrombosis in aPL carriers.

Can Pharmacological Conditioning as an Add-On Treatment Optimize Standard Pharmacological Treatment in Patients with Recent-Onset Rheumatoid Arthritis? A Proof-of-Principle Randomized Clinical Trial.

Medication regimens using conditioning via variable reinforcement have shown similar or improved therapeutic effects as full pharmacological treatment, but evidence in patient populations is scarce. This proof-of-principle double-blind randomized clinical trial examined whether treatment effects in recent-onset rheumatoid arthritis (RA) can be optimized through pharmacological conditioning. After four months of standardized treatment (n = 46), patients in clinical remission (n = 19) were randomized to the Control group (C), continuing standardized treatment (n = 8), or the Pharmacological Conditioning (PC) group, receiving variable treatment according to conditioning principles (n = 11). After eight months, treatment was tapered and discontinued linearly (C) or variably (PC). Standard treatment led to large improvements in disease activity and HRQoL in both groups. The groups did not differ in the percentage of drug-free clinical remission obtained after conditioning or continued standard treatment. The PC group did show a larger decrease in self-reported disease activity (Cohen's d = 0.9) and a smaller increase in TNF-α levels (Cohen's d = 0.7) than the C group. During all phases, more differences between groups were found for the patients who followed protocol than for the intention-to-treat sample. Although the results are not conclusive, pharmacological conditioning may have some advantages in terms of disease progression and stability, especially during the conditioning phase, compared with standard clinical treatment. The effects may be particularly beneficial for patients who show a good initial response to increased medication dosages.

Anti-carbamylated protein antibodies in systemic sclerosis.

BACKGROUND: To investigate the presence of different isotypes of anti-carbamylated protein (CarP) antibodies in systemic sclerosis (SSc) patients and its association with skin involvement. METHODS: Sera of 194 SSc patients from the Leiden CCISS cohort, fulfilling ACR/EULAR 2013 criteria and a clinical diagnosis of SSc, 83 patients with other connective tissue diseases/Raynaud's Phenomenon, 24 rheumatoid arthritis patients and 98 age and sex-matched healthy controls were tested for the presence of anti-CarP IgG, IgA and IgM, determined by ELISA. Clinical characteristics, that were evaluated in SSc patients, included age, anti-topoisomerase antibodies (ATA), anti-centromere antibodies (ACA) and modified Rodnan Skin Score (mRSS). RESULTS: The SSc patients were 55 (SD:13) years and 155 (80%) were female. Forty-four (23%) patients tested positive for ATA, and 80 (42%) ACA. The median mRSS was 2 (range: 0; 47). Prevalence of anti-CarP IgG was higher in SSc patients than in healthy controls (8% vs 3%, p = 0.007. Prevalence of anti-CarP IgA and IgM and levels of anti-CarP isotypes were comparable between SSc patients and healthy controls. Fifteen (8%) SSc patients tested positive for anti-CarP IgG, 16 (8%) for anti-CarP IgA, and 36 (19%) for anti-CarP IgM. There were no significant correlations between age and levels of anti-CarP isotypes. No correlation between anti-CarP IgG levels and mRSS was found (r = 0.141, p = 0.049), nor for anti-CarP IgM and IgA levels. Anti-CarP IgA levels were higher in ATA compared to ACA positive SSc patients (ATA: 616 aU/ml [359; 1103]; ACA: 424 aU/ml [300; 673], p = 0.015). CONCLUSION: SSc patients can test positive for Anti-CarP IgG, IgA and IgM. We do not observe a relevant clinical association between anti-CarP antibody response and skin involvement in SSc.

Response to Biologic Drugs in Patients With Rheumatoid Arthritis and Antidrug Antibodies.

Importance: There are conflicting data on the association of antidrug antibodies with response to biologic disease-modifying antirheumatic drugs (bDMARDs) in rheumatoid arthritis (RA). Objective: To analyze the association of antidrug antibodies with response to treatment for RA. Design, Setting, and Participants: This cohort study analyzed data from the ABI-RA (Anti-Biopharmaceutical Immunization: Prediction and Analysis of Clinical Relevance to Minimize the Risk of Immunization in Rheumatoid Arthritis Patients) multicentric, open, prospective study of patients with RA from 27 recruiting centers in 4 European countries (France, Italy, the Netherlands, and the UK). Eligible patients were 18 years or older, had RA diagnosis, and were initiating a new bDMARD. Recruitment spanned from March 3, 2014, to June 21, 2016. The study was completed in June 2018, and data were analyzed in June 2022. Exposures: Patients were treated with a new bDMARD: adalimumab, infliximab (grouped as anti-tumor necrosis factor [TNF] monoclonal antibodies [mAbs]), etanercept, tocilizumab, and rituximab according to the choice of the treating physician. Main Outcomes and Measures: The primary outcome was the association of antidrug antibody positivity with EULAR (European Alliance of Associations for Rheumatology; formerly, European League Against Rheumatism) response to treatment at month 12 assessed through univariate logistic regression. The secondary end points were the EULAR response at month 6 and at visits from month 6 to months 15 to 18 using generalized estimating equation models. Detection of antidrug antibody serum levels was performed at months 1, 3, 6, 12, and 15 to 18 using electrochemiluminescence (Meso Scale Discovery) and drug concentration for anti-TNF mAbs, and etanercept in the serum was measured using enzyme-linked immunosorbent assay. Results: Of the 254 patients recruited, 230 (mean [SD] age, 54.3 [13.7] years; 177 females [77.0%]) were analyzed. At month 12, antidrug antibody positivity was 38.2% in patients who were treated with anti-TNF mAbs, 6.1% with etanercept, 50.0% with rituximab, and 20.0% with tocilizumab. There was an inverse association between antidrug antibody positivity (odds ratio [OR], 0.19; 95% CI, 0.09-0.38; P < .001) directed against all biologic drugs and EULAR response at month 12. Analyzing all the visits starting at month 6 using generalized estimating equation models confirmed the inverse association between antidrug antibody positivity and EULAR response (OR, 0.35; 95% CI, 0.18-0.65; P < .001). A similar association was found for tocilizumab alone (OR, 0.18; 95% CI, 0.04-0.83; P = .03). In the multivariable analysis, antidrug antibodies, body mass index, and rheumatoid factor were independently inversely associated with response to treatment. There was a significantly higher drug concentration of anti-TNF mAbs in patients with antidrug antibody-negative vs antidrug antibody-positive status (mean difference, -9.6 [95% CI, -12.4 to -6.9] mg/L; P < 001). Drug concentrations of etanercept (mean difference, 0.70 [95% CI, 0.2-1.2] mg/L; P = .005) and adalimumab (mean difference, 1.8 [95% CI, 0.4-3.2] mg/L; P = .01) were lower in nonresponders vs responders. Methotrexate comedication at baseline was inversely associated with antidrug antibodies (OR, 0.50; 95% CI, 0.25-1.00; P = .05). Conclusions and Relevance: Results of this prospective cohort study suggest an association between antidrug antibodies and nonresponse to bDMARDs in patients with RA. Monitoring antidrug antibodies could be considered in the treatment of these patients, particularly nonresponders to biologic RA drugs.

Repair of joint damage in patients with rheumatoid arthritis does not relate to previous suppression of inflammation: a subanalysis after 8 years treat-to-target in the BeSt-trial.

OBJECTIVES: To investigate whether repair of erosions and joint space narrowing (JSN) in rheumatoid arthritis (RA) occurs and whether clinical variables predict this. METHODS: Eight-year follow-up data of the BeSt-study were used. Patients with recent onset RA (1987 criteria) were randomised to four treatment strategies and treated-to-target (Disease Activity Score (DAS)≤2.4). Yearly radiographs of hands and feet were scored in non-chronological order by four independent readers, using the Sharp/van der Heijde score (SHS). Damage repair was defined as a negative ΔSHS in an individual joint, seen by ≥3 out of 4 readers and persisting ≥2 consecutive years. Associations between repair and DAS, prednisone use, infliximab use, anticitrullinated protein antibody, gender, age, body mass index, symptom duration and randomisation arm were investigated with logistic regression analyses, corrected for mean SHS. RESULTS: Repair was seen in 17 patients (5.3%); 10 had regression of JSN, 7 of erosions, none had both. There were no significant associations in any of the regression analyses. CONCLUSION: After 8 years of treatment to target DAS≤2.4 in 508 patients with recent onset RA, repair of JSN and erosions was seen in 17/320 patients (5.3%). Probably due to the rarity of repair, we found no associations with suppression of disease activity or other predictors and repair.

Step forward in early recognition of systemic sclerosis: data from the Leiden CCISS cohort.

BACKGROUND: Since 2009, Dutch patients with a confirmed diagnosis/suspicion of systemic sclerosis (SSc) can be referred to the Leiden Combined Care in Systemic Sclerosis (CCISS) cohort. This study evaluated whether early recognition of SSc has improved over time and whether disease characteristics and survival has changed over time. METHODS: 643 SSc patients fulfilling American College of Rheumatology/European Alliance of Associations for Rheumatology 2013 SSc criteria were included and categorised into three groups based on cohort-entry year: (1) 2010-2013 (n=229 (36%)), (2) 2014-2017 (n=207 (32%)) and (3) 2018-2021 (n=207 (32%)). Variables including disease duration, interstitial lung disease (ILD), digital ulcers (DU), diffuse cutaneous SSc (dcSSc), antitopoisomerase (ATA) and anticentromere (ACA) antibodies, and survival from disease onset were compared between cohort-entry groups, including analyses stratified for sex and autoantibodies. RESULTS: Over time, duration between onset of disease symptoms and cohort entry decreased in males and females, but was always longer in females than in males.The proportion of patients presenting with DU decreased, especially in ACA+SSc patients. Almost no ACA+ patients presented with ILD, while in ATA+ patients this proportion was 25% in 2010-2013 and decreased to 19% in 2018-2021. A reduction in patients presenting with clinically meaningful ILD and dcSSc was observed.Overall 8-year survival for males was 59% (95% CI 40% to 73%) and for females 89% (95% CI 82% to 93%). Eight-year survival showed a trend for improvement over time, and was always worse in males. CONCLUSION: We observed a decrease in disease duration in Leiden CCISS cohort at cohort entry, possibly indicating more timely diagnosis of SSc. This could provide opportunities for early interventions. While symptom duration at presentation is longer in females, mortality is consistently higher in males, underlining the urge for sex-specific treatment and follow-up.

Patterns of clinical joint inflammation in juvenile idiopathic arthritis.

OBJECTIVES: We studied patterns of joint inflammation in juvenile idiopathic arthritis (JIA) to assess whether joint activity recurs locally in the same joints. METHODS: Joints of 91 patients of the BeSt for Kids study, a treat-to-target trial for children with recent-onset oligoarticular, rheumatoid factor-negative polyarticular and psoriatic JIA, were clinically assessed during 2 years (10 study visits). The association between joint inflammation at baseline and later inflammation in the same joint was assessed using a multilevel mixed-effects logistic regression model at joint level. With a Poisson model, the association between baseline joint inflammation and the number of study visits at which the same joint was recurrently inflamed was tested. RESULTS: Of the 6097 joints studied, 15% (897) was clinically inflamed at baseline. In 42% (377/897) of those joints, inflammation recurred during follow-up. Joint inflammation at baseline was statistically significantly associated with joint inflammation during follow-up in the same joint (OR 3.9, 95% CI 3.5 to 4.4) and specifically with the number of episodes of recurrent joint inflammation (IRR 1.6, 95% CI 1.2 to 2.1). CONCLUSION: In JIA, joint inflammation has the tendency to recur multiple times in joints that are clinically inflamed at disease onset. This indicates that local factors might play a role in the processes contributing to the occurrence of JIA flares.

Geo-epidemiology of autoantibodies in rheumatoid arthritis: comparison between four ethnically diverse populations.

BACKGROUND: Rheumatoid arthritis (RA) occurs across the globe in different ethnic populations. Most RA patients harbor anti-modified protein antibodies (AMPA); however, it is unclear whether differences exist in autoantibody responses at different geographic locations and between different ethnic groups, which could provide new clues regarding factors underlying autoantibody development. We therefore investigated AMPA prevalence and association with HLA DRB1 alleles and smoking in four ethnically diverse populations on four different continents. METHODS: Anti-carbamylated (anti-CarP), anti-malondialdehyde acetaldehyde (anti-MAA), and anti-acetylated protein antibodies (anti-AcVim) IgG were determined in anti-citrullinated protein antibody-positive Dutch (NL, n = 103), Japanese (JP, n = 174), First Nations Peoples in Canada (FN, n = 100), and black South African (SA, n = 67) RA patients. Ethnicity-matched local healthy controls were used to calculate cut-offs. Risk factors associated with AMPA seropositivity in each cohort were identified using logistic regression. RESULTS: Median AMPA levels were higher in First Nations Peoples in Canada and especially South African patients, as reflected by percentage seropositivity: NL, JP, FN, and SA: anti-CarP: 47%, 43%, 58%, and 76% (p < 0.001); anti-MAA: 29%, 22%, 29%, and 53% (p < 0.001); and anti-AcVim: 20%, 17%, 38%, and 28% (p < 0.001). Total IgG levels also differed markedly, and when autoantibody levels were normalized to total IgG, differences between cohorts became less pronounced. Although there were some associations with AMPA and HLA risk alleles and smoking, none was consistent across all four cohorts. CONCLUSIONS: AMPA against various post-translational modifications could consistently be detected on different continents across ethnically diverse RA populations. Differences in AMPA levels corresponded to differences in total serum IgG levels. This suggests that, despite differences in risk factors, a common pathway may be involved in AMPA development across geographic locations and ethnicities.

Mouth opening in systemic sclerosis: Its course over time, determinants and impact on mouth handicap.

Objective: Decreased maximal mouth opening is a common and disabling manifestation in systemic sclerosis patients. We aimed to study the course of maximal mouth opening, determinants of smaller maximal mouth opening over time and the burden of smaller maximal mouth opening on mouth handicap. Methods: Consecutive systemic sclerosis patients participating in the prospective Leiden Combined Care in systemic sclerosis cohort were included. Annual clinical assessment included maximal mouth opening measurement and mouth handicap evaluation (Mouth Handicap in Systemic Sclerosis scale). Presence of microstomia (maximal mouth opening < 30 mm) was studied. Maximal mouth opening over time was assessed on group level and for all patients individually. Baseline characteristics were analysed for their association with smaller maximal mouth opening over time (linear mixed-effects models). Furthermore, cross-sectional association between maximal mouth opening with Mouth Handicap in Systemic Sclerosis scale was assessed (linear regression analysis). Results: A total of 382 systemic sclerosis patients were studied with median follow-up time of 2.0 years (interquartile range = 0.0-3.0). At baseline, mean maximal mouth opening was 42.2 ± 8.0 mm and 7% suffered from microstomia. Annual decrease of > 5.0 mm in maximal mouth opening during follow-up occurred in 63 patients and was accompanied by increase in disease severity. Disease characteristics at baseline independently predictive for smaller maximal mouth opening over time were: more extended skin subtype; peripheral vasculopathy; pulmonary, renal and gastrointestinal involvement. Smaller maximal mouth opening was significantly associated with more reported mouth handicap. Conclusion: The course of maximal mouth opening is stable in a majority of systemic sclerosis patients. Still, maximal mouth opening over time was smaller in patients with more severe organ involvement. Although microstomia was infrequent, a smaller maximal mouth opening was significantly associated with more mouth handicap, indicating the importance to address maximal mouth opening in routine care of systemic sclerosis patients.