Peptides Bearing Multiple Post-Translational Modifications as Antigenic Targets for Severe Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA) is characterized by the presence of autoantibodies that are of paramount importance for the diagnosis and prognosis of the disease and have been implicated in its pathogenesis. Proteins resulting from post-translational modifications (PTMs) are capable of triggering autoimmune responses important for the development of RA. In this work, we investigate serum antibody reactivity in patients with an established RA against a panel of chimeric peptides derived from fibrin and filaggrin proteins and bearing from one to three PTMs (citrullination, carbamylation and acetylation) by home-designed ELISA tests (anti-AMPA autoantibodies). The role of anti-AMPAs as biomarkers linked to the presence of a more severe RA phenotype (erosive disease with radiological structural damage) and to the presence of interstitial lung disease (ILD), a severe extra-articular manifestation in RA patients entailing a high mortality, was also analyzed. In general, the association with the clinical phenotype of RA was confirmed with the different autoantibodies, and especially for IgA and IgM isotypes. The prevalence of severe joint damage was only statistically significant for the IgG isotype when working with the peptide bearing three PTMs. Furthermore, the median titers were significantly higher in patients with RA-ILD, a finding not observed for the IgG isotype when working with the single- and double-modified peptides.

Anti-Carbamylated Fibrinogen Antibodies Might Be Associated With a Specific Rheumatoid Phenotype and Include a Subset Recognizing In Vivo Epitopes of Its γ Chain One of Which Is Not Cross Reactive With Anti-Citrullinated Protein Antibodies

To identify the targets recognized by anti-carbamylated protein antibodies (anti-CarP) in patients with early Rheumatoid Arthritis (RA), to study the cross-reactivity between anti-CarP and anti-citrullinated protein antibodies (ACPA) and to evaluate their prognostic value. 331 patients (184 RA and 147 other rheumatisms) from the Very Early Arthritis (VErA) French cohort were analyzed. We performed mass spectrometry analysis of RA sera displaying anti-CarP activity and epitope mapping of the carbamylated fibrinogen γ chain to identify immunodominant peptides. The specificity of these targets was studied using competition assays with the major antigens recognized by ACPA. The prognostic value of anti-carbamylated fibrinogen IgG antibodies (ACa-Fib IgG) was compared to that of anti-cyclic citrullinated peptide antibodies (anti-CCP) and anti-CarP using an in-house ELISA. Besides the α chain, the γ chain of fibrinogen, particularly one immunodominant epitope that has a specific reactivity, was identified as a circulating carbamylated target in sera. The prevalence of ACa-Fib was 37% at baseline and 10.9% for anti-CCP-negative RA. In anti-CCP-negative patients, ACa-Fib positivity was associated with a more inflammatory and erosive disease at baseline but not with rapid radiological progression, which remains strongly related to anti-CCP antibodies. Fibrinogen seems to be one of the antigens recognized in vivo by the anti-CarP response, particularly 2 epitopes of the γ chain, one of which is not cross reactive with ACPA. This specificity might be associated with a distinct clinical phenotype since ACa-Fib IgG were shown to be linked to systemic inflammation in very early RA but not to rapid radiological progression.

Associations between joint pathologies and central sensitization in persons with hand osteoarthritis: results from the Nor-Hand study

Objective Pain sensitization is associated with pain severity in persons with hand OA. What contributes to pain sensitization is unclear. This study explores whether hand OA pathologies and symptom duration are related to central sensitization. Method Participants with hand OA in the Nor-Hand study underwent bilateral hand radiography and US examination. Central sensitization was assessed with pressure pain thresholds (PPT) at remote sites (wrist, trapezius and tibialis anterior muscles) and temporal summation. We examined whether hand OA pathologies, independent of each other, including structural severity (Kellgren–Lawrence sum score, presence of erosive hand OA), inflammatory severity (greyscale synovitis and power Doppler activity sum scores) and symptom duration, were related to central sensitization, adjusting for age, sex, BMI, comorbidities and OA-severity of knee/hip. Results In 291 participants (88% women, median age 61 years, interquartile range 57–66 years) Kellgren–Lawrence, greyscale synovitis and power Doppler activity sum scores were not associated with lower PPTs at remote sites. Persons with erosive hand OA had lower PPTs at the wrist (adjusted beta −0.75, 95% CI −1.32, −0.19) and tibialis anterior (adjusted beta −0.82, 95% CI −1.54, −0.09) and had greater temporal summation (adjusted beta 0.56, 95% CI 0.12, 1.01) compared with persons with non-erosive disease. No associations were found for symptom duration. Conclusions A person’s overall amount of structural or inflammatory hand OA pathologies was not associated with central sensitization. Although persons with erosive hand OA showed greater signs of central sensitization, the small differences suggest that central sensitization is mainly explained by factors other than joint pathologies.

788 VARIABLE GEOGRAPHICAL DIFFERENCES OF AMBULATORY ESOPHAGEAL REFLUX MONITORING IN MEXICO

Ambulatory esophageal reflux monitoring (AEpH) is useful in evaluating persistent or refractory esophageal symptoms despite adequate pharmacologic and/or surgical therapy. There is limited information whether there are geographical or regional differences in the diagnostic outcome of this test. Aim Characterize the diagnostic outcome of AEpH in a diverse population of Mexico. Analyze whether there is regional geographical diagnostic variability. Methods Data was collected from four major referral centers representing diverse geographical areas of Mexico: Mexico City-Central (two centers, years 2016-2020), Veracruz-South (years 2015-2020) and Monterrey-North (years 2013-2020). Consecutive patients undergoing AEpH with persistent GERD symptoms despite PPI therapy and negative upper endoscopy (no erosive disease >C or D LA classification) were entered into a data base and analyzed. Patients were classified as: NERD (acid exposure time (AET > 6.0%); hypersensitive esophagus (normal AET and positive symptom index (SI) or positive symptom association probability [SAP]); functional heartburn (NL AET, neg SI/SAP). Statistics: ANOVA, Chi-square and descriptive methods were used to compare variables among groups. Results 969 cases met inclusion criteria: 311 (32.1%) Central, 430 (44.3%) South, and 228 (23.5%) North. The results are summarized in the table. There were more women 618(63.8%) than men 351(36.2%); p < 0.001 with a mean age 47.7 ± 14.3. Patients were older in Central-Mexico 49.3 ± 13.6 years vs South 47.5 ± 15 and North 46.1 ± 13.6; p = 0.033. Functional heartburn was the most common diagnosis overall and more prevalent in Central-Mexico 171(55%) vs North 97(42.5%) and South 160(37.2%); p < 0.001. NERD was more predominant in the South 171(39.8%) vs North 72(31.6%) and Central-Mexico 98(31.5%); p = 0.029. Hypersensitive esophagus was more frequent in the North 59(25.9%) vs South 99(23%), and Central 42(13.5%); p < 0.001. Conclusion This is the first large data base study to evaluate the outcome of ambulatory esophageal reflux pH testing in Mexico. Our findings indicate a geographical variability of GERD phenotypes and suggest that further investigations are warranted to determine the causes of this distribution.

Autoantibodies against unmodified and citrullinated human endogenous retrovirus K envelope protein in rheumatoid arthritis patients

Objective Autoantibodies against proteins encoded by human endogenous retrovirus K (HERV-K) have been reported in patients with rheumatoid arthritis (RA), but their relevance, if any, has remained unresolved. We revisited this question and tested if such autoantibodies may react with citrullinated epitopes on the envelope (Env) protein of HERV-K. Methods Immunoblotting and ELISAs were conducted with unmodified Env protein and with Env citrullinated by protein arginine deiminase (PAD) 4. Sera from 100 RA patients, plasma from 32 juvenile idiopathic arthritis (JIA) patients, and healthy adult and pediatric controls were included. Antibody reactivity was evaluated for correlations with clinical and laboratory parameters of the patients. Results We replicated and expanded upon published data that patients with RA or JIA have autoantibodies against HERV-K Env, some with high titers. Anti-HERV-K antibodies correlated with cigarette smoking and with circulating DNA-myeloperoxidase complexes indicative of nonapoptotic neutrophil cell death. Furthermore, most of the RA patients, but not JIA patients, had autoantibodies that reacted more strongly with Env that was citrullinated by PAD4. These anticitrullinated Env autoantibodies correlated with seropositivity and tended to be higher in patients with erosive disease. Conclusion Our data suggest that anti-HERV-K immunity is elevated in RA and JIA and may have a connection with pathogenic protein citrullination in RA.

POS1467-HPR SEVERE RESPIRATORY INFECTIONS IN RHEUMATOID ARTHRITIS PATIENTS WITH BIOLOGIC THERAPY. COMPARATIVE STUDY BETWEEN VACCINATED AND NON VACCINATED PATIENTS

Background:Rheumatoid arthritis (RA) patients are at increased risk of severe infections due to the disease itself, and the immunosuppressive treatment. Vaccination programs are designed to decrease the risk of infections.Objectives:In patients with RA treated with biologic therapy (BT) our aim was to assess a) the incidence of severe respiratory infections and b) to compare the risk between vaccinated and non vaccinated patients.Methods:Observational study of 431 patients diagnosed with RA that iniciated BT. One group of patients participated in a vaccination program from October 2011 to October 2016 (Group 1). The other group was not included in the vaccination program (Group 2). The follow-up was made until June 2017 with a minimum follow-up period of 8 months and a maximum of 5.5 years.Information on severe respiratory infections, defined as those that required hospitalization or at least one dose of intravenous antibiotic treatment at the emergency room, was retrieved from the hospital medical records.Results:We studied 431 patients (335 women/96 men); mean age 63.4±13.7 years. In the vaccination program (group 1) were included 299 (69.37%) patients and in the group 2 132 patients (30.63%). The main features of both groups are summarized in Table 1.During the follow-up, we registered 299 hospital admissions due to severe respiratory infections in both groups (incidence density 9.9 (95% CI: 6.9-13.6).In group 1, vaccinated patients, this incidence density was reduced to 7.1 (95% CI: 4.1-11.6). Figure 1.The vaccination program reduced the general incidence of severe respiratory infection in 44%.Conclusion:RA patients with BT included in the vaccination program present a lower incidence of severe respiratory infections compared with non vaccinated patients.Table 1.Main general features at BT onsetGroup 1Vaccination programN=299Group 2Non vaccination programN=132pAge (years) mean±SD61.32±13.0467.97±14.170.32Women, n (%)231 (77.3%)105 (79.5%)0.59Duration of RA (months) mean±SD73.24±10.4112.62±60.2Positive RF/ Positive ACPA, n (%)177(59.2)/172 (57.52%)93(70.5%)98 (74.24%)0.02/0,01Erosive disease, n (%)116 (38.8%)70 (53%)0.06Vasculitis, n (%)15 (5%)2 (1.5%)0.08Interstitial lung disease n (%)12 (4%)7 (5.3%)0.54Subcutaneous nodules n (%)16 (5.4%)6 (4.5%)0.72Corticosteroids299 (100%)132 (100%)1Number of conventional DMARDs, mean±SD1.66±0.892.03±1.050.3Figure 1.Disclosure of Interests:None declared

AB0112 TNF INHIBITOR MONOTHERAPY IN RHEUMATOID ARTHRITIS: IS THERE REALLY A DIFFERENCE IN COMPARISON WITH COMBINATION THERAPY WITH CSDMARDS IN REAL-LIFE?

Background:In Rheumatoid Arthritis (RA), tumor necrosis factor inhibitors (TNFi) in combination with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) has shown advantages concerning efficacy and immunogenicity in comparison with monotherapy. However, in clinical practice, up to 40% of patients under biological DMARDs (bDMARDs) are on monotherapy.Objectives:To compare the efficacy outcomes of TNFi in monotherapy and in combination therapy in a RA monocentric cohort.Methods:Retrospective, cross-sectional study including all the RA patients under TNFi followed at our Rheumatology Department and registered in the national database. Demographic, clinical and laboratorial data and disease activity measures were collected at the last visit of 2019 from each patient. Mann-Whitney U and chi-square tests were used to the comparison analysis between the two groups (continuous and categorical variables, respectively).Results:A total of 144 patients were included: 84% were females; at the last visit of 2019, the mean age was 56.3±10.9 years and the mean disease duration was 18.3±10.2 years; 73.6% were positive for rheumatoid factor (RF), 81.9% for anti-citrullinated protein autoantibodies (ACPA) and 45.1% had erosive disease. There were no statistically significant differences in these variables between the monotherapy and the combination therapy groups (table 1).Table 1.Demographic and disease-related variables in the monotherapy and the combination therapy group.Monotherapy(n=31)Combination therapy (n=113)Age - mean±SD59.1±14.0 years55.5±9.8 yearsDisease duration - mean±SD20.5±11.2 years17.7±9.7 yearsRF positive - n (%)20 (60.4%)86 (76.8%)ACPA positive - n (%)25 (80.6%)93 (85.3%)Erosive disease - n (%)15 (48.4%)50 (44.6%)Thirty-one patients (21.5%) were under monotherapy with TNFi and etanercept was the most frequent TNFi in both groups (54.8% vs 50.0%; monotherapy and combination therapy groups, respectively). At the start of the first bDMARD, the monotherapy group had a higher disease activity score 28 - 4 variables (DAS 28 4V; 6.083±0.930 vs 5.605±1.043, p=0.039) and a higher simple disease activity score (SDAI; 36.12±11.77 vs 28.76±9.98, p=0.035); also, in the monotherapy group more patients had already started the bDMARD in monotherapy (22.6% vs 2.7%, p<0.001), less patients were under (38.7% vs 73.2%, p=0.001) or had already been treated with (77.4% vs 93.8%, p=0.007) methotrexate, in comparison with the combination group therapy.At the last visit of 2019, the monotherapy group had a higher mean years of duration of iTNF treatment (5.5±5.8 vs 3.4±4.5, p=0.048), a higher mean patient global assessment - visual analogue scale (PGA-VAS; 49±18 vs 39±25, p=0.023), a higher mean prednisolone equivalent dose in mg/day (7.6±6.3 vs 5.6±3.2, p=0.045) and a lower proportion of American College of Rheumatology 50 and 70 responses (ACR 50: 12.9% vs 17.0%, p=0.023; ACR 70: 3.2% vs 10.7%, p=0.045) in comparison with the combination therapy group.Conclusion:In line with the literature, our real-life results demonstrate some direct (higher PGA-VAS and lower ACR 50 and 70 responses) and indirect (higher current prednisolone equivalent dose) data that suggest that patients with TNFi monotherapy may have a worst disease activity control in comparison with combination therapy.Disclosure of Interests:None declared

POS0444 DIAGNOSTIC VALUE OF HIGH-RESOLUTION PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY COMPARED TO CONVENTIONAL RADIOGRAPHY FOR DETECTING EROSIVE DISEASE IN RHEUMATOID ARTHRITIS

Background:Conventional radiography (CR) of the hands, wrists and feet is currently the gold standard for assessing erosive damage in patients with rheumatoid arthritis (RA). However, CR is prone to relatively low resolution and projection superimposition due to 2-dimensional imaging. Therefore, CR might not detect erosive disease in RA patients. High-resolution peripheral quantitative computed tomography (HR-pQCT) is an imaging modality with superior resolution (82µm3) to all other imaging modalities in vivo. However, HR-pQCT imaging is limited by a smaller field of view. Therefore, it needs to be illuminated, whether the higher resolution of HR-pQCT imaging is sufficient for diagnosing erosive disease in patients with RA despite the limited field of view.Objectives:The objective was to investigate whether High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) of just two metacarpophalangeal (MCP) joints can diagnose more patients having erosive RA than conventional radiography (CR) of 44 joints in the hands, wrist and feet.Methods:In this single-centre cross-sectional study. Patients with established RA (disease duration ≥ 5 years) were investigated by HR-pQCT and CR. The second and third MCP joints of the dominant hand were assessed for erosions by HR-pQCT. CR in the hands, wrist and feet were scored according to the Sharp/van der Heijde (SHS) method.Results:Three hundred fifty-four patients were included. By CR, 67 (18.9%) patients were classified with non-erosive RA, and 287 (81.1%) with erosive RA. In the 67 patients with non-erosive RA, 47 patients (70.1%) had erosions in the second and third MCP joints by HR-pQCT (Figure 1). We found an agreement between CR and HR-pQCT for 274 (77.4%) of the patients. The sensitivity and specificity (95%CI) of HR-pQCT for diagnosing erosive RA when CR of hands, wrist and feet were used as the reference was 89% (84 – 92) % and 30% (19 – 42) %, respectively. Using HR-pQCT for two MCP joints as the reference, the sensitivity and specificity of CR of hands, wrist and feet for diagnosing erosive RA were 84% (80 – 88) % and 38% (25 – 52) %, respectively. The McNemar’s χ2 test for diagnosing patients having erosive RA between the two modalities was 2.45, p = 0.146.Conclusion:HR-pQCT imaging identifies erosions which are not seen by CR. Using HR-pQCT at of the second and third MCP joint reclassified a substantial number of patients as having erosive RA compared to their non-erosive state determined by CR. The sensitivity and specificity of diagnosing patients having erosive RA using HR-pQCT from only two fingers were not statistically different from CR of 44 joints, in the hands, wrist and feet.Acknowledgements:The authors, we want to acknowledge Aarhus University, The Danish Rheumatism Association, Novo Nordic Foundation and A.P. Møller Fonden who have financially supported the study. The funding sources did not have any role in the collection, analysis and interpretation of data. The authors are grateful for the excellent assistance in recruiting and scheduling the patients by Mia Marie Remmer, Lone Thomasen and Else Sloth Rousing.Disclosure of Interests:Rasmus Klose-Jensen: None declared, Josephine Therkildsen: None declared, Anne-Birgitte Blavnsfeldt: None declared, Bente Langdahl Speakers bureau: Eli Lilly, Amgen, UCB, Gilead, and Gideon-Richter, Grant/research support from: Novo Nordisk and Amgen, Kresten Krarup Keller: None declared, Ellen-Margrethe Hauge Speakers bureau: MSD, Pfizer, UCB, and Sobi., Grant/research support from: Roche, Novartis and Novo Nordic Foundation.

AB0270 EFFECTIVENESS OF A SWITCH FROM TOFACITINIB TO BARICITINIB IN RHEUMATOID ARTHRITIS: A RETROSPECTIVE ANALYSIS OF REAL-WORLD DATA IN SWITZERLAND

Background:Janus Kinase Inhibitors (JAKi) have recently been approved for the treatment of rheumatoid arthritis (RA) over the last years. JAKi differ in their specificity for the different JAK family members (JAK1, JAK2, JAK3 and TYK2). All three JAKis that are currently approved in Switzerland seem to have comparable efficacy on different disease stages of RA. Whether a JAKi can be effective after discontinuation of another JAKi is one of the open questions of interest according to the EULAR RA guidelines [1].Objectives:To study the effectiveness of baricitinib in patients with RA after discontinuation of tofacitinib.Methods:Longitudinal, retrospective chart review conducted between October 2019 and December 2020 of patients with RA at two Swiss centers (Kantonsspital Aarau and Inselspital Bern). Disease activity was assessed by DAS 28.Results:12 patients (1 male, 11 female) were treated with 4mg baricitinib/d after tofacitinib was discontinued. Mean age of the patients was 61 years, disease duration 140 months. Patients were previously treated with at least two conventional synthetic DMARDs and 75% with at least one biological DMARD. 58% of patients were positive for ACPA, 42% for rheumatoid factor. 50% of the patients suffered from erosive disease. Tofacitinib was stopped in 92% of the patients because of an insufficient response after a mean of 25.8 months. Moderate EULAR response was achieved in 83.3% of the patients after an average of 8 months treatment with baricitinib, and good EULAR response in 58.3% after an average of 10 months. There were no serious adverse events, neoplasms, opportunistic or serious infections during follow-up.Conclusion:The first retrospective analysis of real-world data of baricitinib following tofacitinib shows that there is a good clinical response in 70% of cases. Although limited by the number of patients this study therefore supports the notion that baricitinib after discontinuation of tofacitinib in RA patients may be an effective therapeutic option.References:[1]Smolen JS, Landewé RBM, Bijlsma JWJ, et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2019 update. Annals of the Rheumatic Diseases. 2020;79(6):685-699. doi:10.1136/annrheumdis-2019-216655, p. 695Disclosure of Interests:Simon Kellerhals: None declared, Jennifer Amsler: None declared, Hendrik Schulze-Koops: None declared, Thomas Hügle Consultant of: GSK, Abbvie, Pfizer, Jansen, Novartis, Eli Lilly., Michael J. Nissen Consultant of: Abbvie, Celgene, Eli-Lilly, Janssen, Novartis and Pfizer., Hasler paul Consultant of: Abbvie, Lilly, Diego Kyburz Consultant of: Abbvie, Gilead, Lilly, Novartis and Pfizer, outside of the submitted work, Rudiger Muller Consultant of: Abbvie, Novartis, Grant/research support from: Bebro Pharma