Diffuse large B cell lymphoma in rheumatoid arthritis patients is associated with elevated B-cell driving factors including CXCL13.

Patients with rheumatoid arthritis (RA) are at increased risk of diffuse large B cell lymphoma (DLBCL) compared to the general population. Here, we explored the inflammatory profiles in the blood of RA patients who had developed DLBCL. RA-DLBCL patients had significantly higher levels of the pro-inflammatory markers TNF, IL-8, CXCL9, APRIL, and particularly CXCL13 (median 796 vs.

Recognition of Glycine Versus Nonglycine Citrulline Motifs Dictating the HLA Class II Association of Anticitrullinated Protein Antibodies: Insights From Autoantibody Profiling of 6,900 Scandinavian Patients With Rheumatoid Arthritis.

Objective: Rheumatoid arthritis (RA)-associated anticitrullinated protein antibodies (ACPAs) target various antigens by binding short citrulline amino acid motifs, resulting in heterogeneous ACPA profiles among patients. Here we analyzed ACPA patterns by recognized citrulline motifs in relation to the RA risk factors HLA-DRB1 shared epitope (SE) alleles and history of smoking.

Methods: Rheumatoid factor (RF) and anticyclic citrullinated peptide (CCP2) isotypes, 15 anti-Cit- and four anti-Carb/Acet-peptide-IgG, were centrally measured in 6,907 patients from five Scandinavian RA cohorts using fluoroenzyme immunoassay and a custom-made multiplex solid-phase microarray.

Revisiting the Link Between HLA-DRB1 Alleles and Autoantibodies in Rheumatoid Arthritis: Association of non-Shared Epitope Alleles *09 and *15 With High Levels of Anti-Citrullinated Peptide/Protein Antibodies.

Objective: Autoantibodies serve as essential clinical biomarkers and may indicate etiological mechanisms in rheumatic diseases. In light of the increasing knowledge concerning the diversity and biologic implications of anti-citrullinated peptide/protein antibodies (ACPAs), we have re-evaluated the association between the ACPA response and the HLA-DRB1 allelic groups, known to represent a major genetic risk factor for rheumatoid arthritis (RA).

Methods: We explored a collection of 4,392 well-characterized incident patients with RA of White European descent from the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) new-onset RA study, as well as 1,199 cases of patients with RA of Southeast Asian origin from the Malaysian EIRA study.

Identification of early risk factors for anti-citrullinated-protein-antibody positive rheumatoid arthritis-a prospective cohort study.

Objective: Individuals positive for anti-cyclic-peptide-antibodies (anti-CCP) and musculoskeletal complaints (MSK-C) are at risk for developing rheumatoid arthritis (RA). In this study we aimed to investigate factors involved in arthritis progression.

Methods: Anti-CCP2-positive individuals with MSK-C referred to a rheumatologist were recruited.

Gastrointestinal symptoms in patients with postural orthostatic tachycardia syndrome in relation to hemodynamic findings and immunological factors.

Gastrointestinal (GI) symptoms are common in postural orthostatic tachycardia syndrome (POTS). We aimed to explore the prevalence and severity of GI symptoms in POTS, and to investigate immunological factors, hemodynamic findings, and their possible association with GI symptoms in POTS. Forty-three patients (93% female, median age 30.

Identification of circulating autoantibodies to non-modified proteins associated with ACPA status in early rheumatoid arthritis.

Objective: The objective of this study was to discover autoantibodies to non-modified proteins associated with the presence/absence of ACPAs in RA.

Methods: The autoantibody repertoire of 80 ACPA-negative and 80 ACPA-positive RA subjects from the Swedish population-based Epidemiological Investigation of RA (EIRA) cohort was screened using a suspension bead array built on protein fragments earlier described as autoimmunity targets. Four autoantibodies positive in the initial screening were validated in another set of EIRA samples containing 317 ACPA-positive, 302 ACPA-negative and 372 age- and sex-matched controls.

In early rheumatoid arthritis, anticitrullinated peptide antibodies associate with low number of affected joints and rheumatoid factor associates with systemic inflammation.

Objectives: To investigate how individual rheumatoid arthritis (RA) autoantibodies associate with individual signs and symptoms at the time of RA diagnosis.

Methods: IgA, IgG, IgM rheumatoid factor (RF), antibodies against cyclic citrullinated peptide version 2 (anti-CCP2) and 16 individual antibodies against citrullinated protein (ACPA) reactivities were analysed centrally in baseline sera from 1600 patients with RA classified according to the 1987 American College of Rheumatology (ACR) criteria. These results were related to C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), number of swollen and tender joints (SJC and TJC), 28-joint disease activity scores (DAS28 and DAS28CRP), global disease activity evaluated by the patients and Health Assessment Questionnaire, all obtained at baseline.

Autoreactive B cells against malondialdehyde-induced protein cross-links are present in the joint, lung, and bone marrow of rheumatoid arthritis patients.

Autoantibodies to malondialdehyde (MDA) proteins constitute a subset of anti-modified protein autoantibodies in rheumatoid arthritis (RA), which is distinct from citrulline reactivity. Serum anti-MDA IgG levels are commonly elevated in RA and correlate with disease activity, CRP, IL6, and TNF-α. MDA is an oxidation-associated reactive aldehyde that together with acetaldehyde mediates formation of various immunogenic amino acid adducts including linear MDA-lysine, fluorescent malondialdehyde acetaldehyde (MAA)-lysine, and intramolecular cross-linking.

Presence of anti-modified protein antibodies in idiopathic pulmonary fibrosis.

Background And Objective: Studies of autoimmunity and anti-citrullinated protein antibodies (ACPA) in idiopathic pulmonary fibrosis (IPF) have been confined to investigations of anti-cyclic citrullinated peptide (anti-CCP) antibodies which utilize synthetic peptides as surrogate markers for in vivo citrullinated antigens. We studied immune activation by analysing the prevalence of in vivo anti-modified protein antibodies (AMPA) in IPF.

Methods: We included patients with incident and prevalent IPF (N = 120), sex and smoking-matched healthy controls (HC) (N = 120) and patients with RA (N = 104).

Rheumatoid Arthritis-Specific Autoimmunity in the Lung Before and at the Onset of Disease.

Objective: The lung is implicated as a site for breach of tolerance prior to onset of seropositive rheumatoid arthritis (RA). To substantiate this, we investigated lung-resident B cells in bronchoalveolar lavage (BAL) samples from untreated early RA patients and anti-citrullinated protein antibody (ACPA)-positive individuals at risk for developing RA.

Methods: Single B cells (n = 7,680) were phenotyped and isolated from BAL samples from individuals at risk of RA (n = 3) and at RA diagnosis (n = 9).

Anti-Citrullinated Protein Antibody Reactivity towards Neutrophil-Derived Antigens: Clonal Diversity and Inter-Individual Variation.

Background: Why the adaptive immune system turns against citrullinated antigens in rheumatoid arthritis (RA) and whether anti-citrullinated protein antibodies (ACPAs) contribute to pathogenesis are questions that have triggered intense research, but still are not fully answered. Neutrophils may be crucial in this context, both as sources of citrullinated antigens and also as targets of ACPAs. To better understand how ACPAs and neutrophils contribute to RA, we studied the reactivity of a broad spectrum of RA patient-derived ACPA clones to activated or resting neutrophils, and we also compared neutrophil binding using polyclonal ACPAs from different patients.

The impact of immunomodulating treatment on the immunogenicity of COVID-19 vaccines in patients with immune-mediated inflammatory rheumatic diseases compared to healthy controls. A Swedish nationwide study (COVID19-REUMA).

Objectives: To elucidate antibody responses after the second and third dose of COVID-19 vaccine in patients with inflammatory rheumatic diseases (IRD) treated with biologic/targeted disease modifying anti-rheumatic drugs (b/ts DMARDs).

Methods: Antibody levels to antigens representing spike full length protein and spike S1 were measured before vaccination, 2-12 weeks after the second dose, before and after the third dose using multiplex bead-based serology assay. Positive antibody response was defined as antibody levels over cut off (seropositivity) in seronegative individuals or ≥ 4-fold increase in antibodies in individuals seropositive for both spike proteins.

The human bone marrow plasma cell compartment in rheumatoid arthritis - Clonal relationships and anti-citrulline autoantibody producing cells.

A majority of circulating IgG is produced by plasma cells residing in the bone marrow (BM). Long-lived BM plasma cells constitute our humoral immune memory and are essential for infection-specific immunity. They may also provide a reservoir of potentially pathogenic autoantibodies, including rheumatoid arthritis (RA)-associated anti-citrullinated protein autoantibodies (ACPA).

The association between autoantibodies and risk for venous thromboembolic events among patients with rheumatoid arthritis.

Objectives: To assess the association between venous thromboembolic (VTE) events and autoantibodies, following patients from RA diagnosis, measuring occurrence, levels and collective load of different autoantibodies against post-translational protein modifications, in particular recognizing citrullination (e.g. citrullinated fibrinogen) and RF by isotype.

Anti-citrullinated protein antibody specificities and pulmonary fibrosis in relation to genetic loci in early rheumatoid arthritis.

Objectives: Pulmonary manifestations in RA are common comorbidities, but the underlying mechanisms are largely unknown. The added value of a multiplex of ACPA and genetic risk markers was evaluated for the development of pulmonary fibrosis (PF) in an inception cohort.

Methods: A total of 1184 patients with early RA were consecutively included and followed prospectively from the index date until death or 31 December 2016.

Antibodies to a Citrullinated Epitope Are Increased in Early Rheumatoid Arthritis, and Can Be Produced by Gingival Tissue B Cells: Implications for a Bacterial Origin in RA Etiology.

Based on the epidemiological link between periodontitis and rheumatoid arthritis (RA), and the unique feature of the periodontal bacterium to citrullinate proteins, it has been suggested that production of anti-citrullinated protein antibodies (ACPA), which are present in a majority of RA patients, may be triggered in the gum mucosa. To address this hypothesis, we investigated the antibody response to a citrullinated peptide in relation to the autoimmune ACPA response in early RA, and examined citrulline-reactivity in monoclonal antibodies derived from human gingival B cells. Antibodies to a citrullinated peptide derived from (denoted CPP3) and human citrullinated peptides were analyzed by multiplex array in 2,807 RA patients and 372 controls; associations with RA risk factors and clinical features were examined.

A Comprehensive Evaluation of the Relationship Between Different IgG and IgA Anti-Modified Protein Autoantibodies in Rheumatoid Arthritis.

Seropositive rheumatoid arthritis (RA) is characterized by the presence of rheumatoid factor (RF) and anti-citrullinated protein autoantibodies (ACPA) with different fine-specificities. Yet, other serum anti-modified protein autoantibodies (AMPA), e.g.

Rheumatoid arthritis autoantibodies and their association with age and sex.

Objectives: To examine the association between individual rheumatoid arthritis (RA) autoantibodies, sex and age at RA onset.

Methods: Anti-CCP2, IgA-, IgG- and IgM-RF were analysed centrally in baseline sera from 1600 RA patients diagnosed within one year of RA symptom onset. Cut-offs for RF isotypes were determined at the 98th percentile based on RA-free controls, close to the 98.

Presence of autoantibodies in "seronegative" rheumatoid arthritis associates with classical risk factors and high disease activity.

Background: Rheumatoid arthritis (RA) is classified as seropositive or seronegative, depending on the presence/absence of rheumatoid factor (RF), primarily IgM RF, and/or anti-citrullinated protein antibodies (ACPA), commonly detected using anti-cyclic citrullinated peptide (CCP) assays. Known risk factors associate with the more severe seropositive form of RA; less is known about seronegative RA. Here, we examine risk factors and clinical phenotypes in relation to presence of autoantibodies in the RA subset that is traditionally defined as seronegative.

Different Hierarchies of Anti-Modified Protein Autoantibody Reactivities in Rheumatoid Arthritis.

Objective: Anti-citrullinated protein antibodies (ACPAs) are a hallmark of seropositive rheumatoid arthritis (RA). Yet, the precise disease-relevant autoantigens that are targeted by ACPAs remains a matter of debate. This study utilized patient-derived monoclonal ACPAs, rather than serum autoantibody analysis, to characterize the multireactivity to different protein modifications and to reveal autoantibody subsets in patients with RA.

Anti-Citrullinated Protein Antibody Specificities, Rheumatoid Factor Isotypes, and Incident Cardiovascular Events in Patients With Rheumatoid Arthritis.

Objective: To investigate the relationship between anti-citrullinated protein antibodies (ACPAs), specific ACPA subspecificities, rheumatoid factor (RF) isotypes, and incident cardiovascular (CV) events in patients with rheumatoid arthritis (RA).

Methods: Serum samples from Swedish patients with new-onset RA (diagnosed within 1 year of symptom onset between 1996 and 2009) were centrally typed for anti-cyclic citrullinated peptide 2 (anti-CCP2) antibodies, 20 ACPA subspecificities, and RF isotypes. Patients were followed up longitudinally in nationwide registers to monitor the occurrence of acute coronary syndrome (ACS), stroke, CV-related death, and major adverse CV events (MACE).

Rheumatoid arthritis patients display B-cell dysregulation already in the naïve repertoire consistent with defects in B-cell tolerance.

B cells are postulated to be central in seropositive rheumatoid arthritis (RA). Here, we use exploratory mass cytometry (n = 23) and next-generation sequencing (n = 19) to study B-cell repertoire shifts in RA patients. Expression of several B-cell markers were significantly different in ACPA RA compared to healthy controls, including an increase in HLA-DR across subsets, CD22 in clusters of IgM B cells and CD11c in IgA memory.

A cross-sectional investigation into the association between and autoantibodies to citrullinated proteins in a German population.

Background: (P.g) is unique among pathogens due to its ability to generate citrullinated proteins in an inflammatory milieu, potentially mediating the loss of immune tolerance, the production of anticitrullinated protein antibodies (ACPAs), and subsequently the development of rheumatoid arthritis (RA). Based on this hypothesis, we set out to investigate whether P.

Distinct HLA Associations with Rheumatoid Arthritis Subsets Defined by Serological Subphenotype.

Rheumatoid arthritis (RA) is the most common immune-mediated arthritis. Anti-citrullinated peptide antibodies (ACPA) are highly specific to RA and assayed with the commercial CCP2 assay. Genetic drivers of RA within the MHC are different for CCP2-positive and -negative subsets of RA, particularly at HLA-DRB1.