Objective Anti-citrullinated protein antibodies (ACPAs) are characteristic of rheumatoid arthritis. However, their presence years before onset of clinical RA is perplexing. Although multiple putative citrullinated antigens have been identified, no studies have demonstrated the specific capacity of these antigens to initiate inflammatory arthritis. We sought to recapitulate the transition from preclinical to clinical RA and to demonstrate the capacity of local citrullination to facilitate this transition. Methods We performed proteomic analysis of activated human neutrophils to identify citrullinated proteins including those targeted as part of the RA immune response. Using ELISA we compared RA and OA synovial fluid for levels of citrullinated histone 2B (cH2B) and its immune complex. Using macrophage activation assays we assessed the effect of histone citrullination on immunostimulatory capacity and evaluated the stimulatory capacity of native and citrullinated H2B immune complexes. Finally, we assessed the potential for anti-cH2B antibodies to mediate arthritis in vivo. Results We identified robust targeting of neutrophil-derived citrullinated histones by the ACPA immune response. Over 90% of RA patients have anti-cH2B antibodies. Histone citrullination increases innate immunostimulatory capacity and immune complexes containing citrullinated histones activate macrophage cytokine production and propagate neutrophil activation. Finally, we demonstrate that immunization with H2B is arthritogenic, but only in the setting of underlying articular inflammation. Conclusion We identify citrullinated histones, specifically cH2B as an antigenic target of the ACPA immune response. Furthermore, local generation of citrullinated antigen during low grade articular inflammation provides a mechanistic model for the conversion from preclinical autoimmunity to inflammatory arthritis.

Objective. The U1-70-kd RNP is a prominent target of autoimmunity in connective tissue diseases. In this study, we explored whether its endogenous ligand, U1 RNA, mediates a proimmune signal and may be immunogenic.Methods. We assayed the proliferation of control and MyD88-knockout splenocytes in response to in vitro-synthesized U1 RNA, and measured interleukin-6 (IL-6) and IL-8 secretion induced by U1 RNA in a human cell line competent for signaling through Tolllike receptor 3 (TLR-3) and TLR-5. Conclusion. U1 RNA is capable of inducing manifestations consistent with TLR-3 activation. The ability of U1 RNA (which has a substantial double-stranded secondary structure) to activate TLR-3 may contribute to the immunogenicity of the U1-70-kd autoantigen.Stimulation of innate immunity by native RNA molecules with a double-stranded secondary structure may help explain the high prevalence of autoimmunity to RNA binding proteins.

Background Persistence of biologic therapy in psoriatic arthritis (PsA) patients is an important factor in individualized patient treatment planning and healthcare policy and guideline development. Objective To estimate the persistence of biologic agents prescribed to PsA patients in a real-life setting as well as factors associated with improved biologic drug survival in these patients. Methods Patients with PsA from a large healthcare provider database with at least two consecutive dispensed prescriptions of a biologic agent indicated for PsA from January 1, 2002, until December 31, 2018, were identified and followed until medication stop date or the end of observation period. Patients were considered non-persistent whenever a permissible lag time of 6 months from the time of prescription issuance until medication filling date was exceeded. Treatment changes were based on physician decisions and patient preferences. Demographic data including age, sex, body mass index (BMI), ethnicity, smoking history, and socioeconomic status as well as Charlson comorbidity index were retrieved. Data regarding use of steroids and conventional disease-modifying anti-rheumatic drugs (cDMARDs) were also extracted. Descriptive statistics, including means (standard deviations) for continuous variables and frequencies (%) for categorical variables, were used. Persistence estimates were derived using non-parametric survival analysis using Kaplan-Meier functions, with treatment discontinuations as failure events. Cox regression hazard ratio models were conducted to investigate factors associated with drug persistence. Results A total of 2301 PsA patients with 2958 treatment periods were identified and included in the analyses. Mean age of the study population was 50.9 ± 14 years, 54% were females, 70.4% were with BMI > 25, 40% were current smokers, and 76% were with a Charlson comorbidity index > 1. The most commonly prescribed drug was etanercept (33%), followed by adalimumab (29%), golimumab (12%), secukinumab (10%), ustekinumab (8%), and infliximab (8%). While approximately 40% of patients persisted on therapy following 20 months of treatment, only about 20% of patients remained on any particular biologic agent after 5 years. Analyzing the data for all treatment periods while taking into account all lines of therapy revealed that secukinumab had a higher persistency than adalimumab, infliximab, and ustekinumab, with a log rank of 0.022, 0.047, and 0.001, respectively. Female sex and smoking were associated with lower drug persistence (HR = 1.25, 95% CI = 1.13–1.38 and HR = 1.109, 95% CI = 1.01–1.21, respectively). On analyzing the data using only the first indicated biologic line, no superiority of any single anti-tumor necrosis factor-alpha (anti-TNFα) agent was observed, while secukinumab was found to be superior as second line therapy to adalimumab, etanercept, infliximab, and ustekinumab but not to golimumab with a log rank P value of 0.001, 0.004, 0.025, and 0.002, respectively. Conclusions In this large observational cohort studied in the era of biologic therapy, a relatively low drug persistence was observed, with female sex and smoking having a negative impact on persistency. None of the anti-TNFα agents was found to be more persistent than others as first line therapy, while secukinumab was found to be superior to other biologics when indicated as second line of therapy.

Background:Vaccination represents a cornerstone in mastering the COVID-19 pandemic. Data on immunogenicity, efficacy, and safety of the novel BNT162b2 mRNA vaccine in patients with autoimmune inflammatory rheumatic diseases (AIIRD) are limited.Objectives:To investigate the immunogenicity, efficacy, and safety of the BNT162b2 mRNA vaccine in patients with AIIRD compared to the general population.Methods:A prospective multicenter study investigated immunogenicity, efficacy, and safety of the two-dose regimen BNT162b2 mRNA vaccine in adult patients with AIIRD including rheumatoid arthritis (RA), psoriatic arthritis (PsA), axial spondyloarthropathy (axSpA), systemic lupus erythematosus (SLE), connective tissues diseases (CTD), systemic vasculitides, and idiopathic inflammatory myositis (IIM), compared to control subjects without rheumatic diseases or immunosuppressive therapies. Serum IgG antibody levels against SARS-CoV-2 spike S1/S2 proteins were measured 2 - 6 weeks after the second vaccine dose. Seropositivity was defined as IgG ≥15 binding antibody units (BAU)/ml. Post-vaccination efficacy defined as post-vaccination COVID-19 infection and safety were assessed. Pre- and post- vaccination disease activity indices were assessed as appropriate for each disease.Results:A total of 686 AIIRD patients and 121 controls participated into the study. AIIRD patients were significantly older than controls, mean age±SD 56.76±14.88 vs 50.76±14.68, respectively, p<0.0001. A total of 95.2% (n=653) AIIRD patients were treated with immunomodulatory medications.The seropositivity rate was 86% (n=590) in patients with AIIRD compared to 100% in controls (p <0.0001) The level of the S1/S2 antibodies was significantly reduced in AIIRD patients compared to controls (mean± SD 132.9±91.7 vs 218.6±82.06, P<0.0001). In patients with PsA, AxSpA, SLE, and LVV, the seropositive rate was above 90%. In RA, the seropositive rate was 82.1% and the lowest seropositive rate (<40%) was observed in patients with AAV and IIM.Anti-CD20 significantly impaired the vaccine’s immunogenicity, with the lowest seropositivity rate of 39%. The use of GC, mycophenolate mofetil (MMF), and abatacept was associated with a significantly lower rate of seropositivity (Figure 1). MTX significantly reduced the seropositivity in patients treated with MTX monotherapy and in combinations with other treatments (92% and 84%, respectively), although at a lesser magnitude than anti-CD20, MMF, and abatacept. More than 97% of patients treated with anti-cytokine therapies including TNFi, interleukin-17 and interleukin-6 inhibitors had an appropriate immunogenic response when used as monotherapy. The combination of TNFi with MTX significantly reduced the rate of seropositivity to 93%, p=0.04. Age over 65 years, a diagnosis of RA, IIM, ANCA-associated vascilitis, and treatment with GC, MMF, anti-CD20, and abatacept were associated with a reduced likelihood of seropositivity.Figure 1.Seropositivity rate by immunosuppressive treatment.There were no post-vaccination symptomatic cases of COVID-19 among AIIRD patients and one mild case in the control group. Major adverse events in AIIRD patients included death (n=2) several weeks after the second vaccine dose, non-disseminated herpes zoster (n=6), uveitis (n=2), and pericarditis (n=1). Post-vaccination disease activity remained stable in the majority of patients.Conclusion:Vaccination with the BNTb262 vaccine resulted in an adequate immunogenic response with an acceptable safety profile in the majority of patients with AIIRD. Treatment with GC, rituximab, MMF, and abatacept may impair BNT162b2-induced immunogenicity. Postponing administration of rituximab, when clinically feasible, seems to be reasonable to improve vaccine-induced immunogenicity. Holding treatment with abatacept and MMF may be considered on an individual basis.Disclosure of Interests:None declared