Objective. During the last decade, rheumatologists have learned to initiate disease-modifying antirheumatic drugs (DMARDs) early to improve the outcome of rheumatoid arthritis (RA). However, the effect of delay in assessment by a rheumatologist on the outcome of RA has scarcely been explored. The purpose of this study was to examine the association between delay in assessment by a rheumatologist, rates of joint destruction, and probability of achieving DMARD-free remission in patients with RA. Patient characteristics associated with components of delay (by the patient, by the general practitioner [GP], and overall) were assessed.Methods. A total of 1,674 early arthritis patients from the Leiden Early Arthritis Clinic cohort were evaluated for patient delay, GP delay, and total delay in assessment by a rheumatologist. Among 598 RA patients, associations between total delay, achievement of sustained DMARD-free remission, and the rate of joint destruction over 6 years followup were determined.Results. The median patient, GP, and total delays in seeing a rheumatologist among patients with early arthritis were 2.4 weeks, 8.0 weeks, and 13.7 weeks, respectively. Among all diagnoses, those diagnosed as having RA or spondylarthritis had the longest total delay (18 weeks). Among the RA patients, 69% were assessed in >12 weeks; this was associated with a hazard ratio of 1.87 for not achieving DMARD-free remission and a 1.3 times higher rate of joint destruction over 6 years, as compared with assessment in <12 weeks. Older age, female sex, gradual symptom onset, involvement of the small joints, lower levels of C-reactive protein, and the presence of autoantibodies were associated with longer total delay.Conclusion. Only 31% of the RA patients were assessed in <12 weeks of symptom onset. Assessment in <12 weeks is associated with less joint destruction and a higher chance of achieving DMARD-free remission as compared with a longer delay in assessment. These results imply that attempts to diminish the delay in seeing a rheumatologist will improve disease outcome in patients with RA.

Epitope spreading with an increase in the recognition of citrullinated antigens occurs before the onset of RA. Immunological differences in ACPA fine specificity between UA-UA patients and UA-RA patients are present at baseline and are associated with the future disease course.

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In a genetically predisposed population of NAN patients with RA and their relatives, anti-P. gingivalis antibodies were associated with ACPA. These findings suggest that immune responses to P. gingivalis may be involved in breaking immune tolerance to citrullinated antigens.

Objective. Anti-citrullinated protein antibodies (ACPA) exhibit unique specificity for rheumatoid arthritis. However, it is incompletely understood whether and how ACPA contribute to disease pathogenesis. The Fc part of human IgG carries 2 N-linked glycan moieties that are crucial for the structural stability of the antibody and that modulate both its binding affinity to Fc␥ receptors and its ability to activate complement. We undertook this study to analyze Fc glycosylation of IgG1 ACPA in serum and synovial fluid (SF) in order to further characterize the immune response to citrullinated antigens.Methods. ACPA were isolated by affinity purification using cyclic citrullinated peptides as antigen. IgG1 Fc glycosylation was analyzed by mass spectrometry. ACPA IgG1 glycan profiles were compared with glycan profiles of total serum IgG1 obtained from 85 wellcharacterized patients. Glycan profiles of paired SF and serum samples were available from 11 additional patients.Results. Compared with the pool of serum IgG1, ACPA IgG1 lacked terminal sialic acid residues. In SF, ACPA were highly agalactosylated and lacked sialic acid residues, a feature that was not detected for total SF IgG1. Moreover, differential ACPA glycan profiles were detected in rheumatoid factor (RF)-positive and RFnegative patients.Conclusion. ACPA IgG1 exhibit a specific Fclinked glycan profile that is distinct from that of total serum IgG1. Moreover, Fc glycosylation of ACPA differs markedly between SF and serum. Since Fc glycosylation directly affects the recruitment of Fc-mediated effector mechanisms, these data could further our understanding of the contribution of ACPA to disease pathogenesis.Antibodies relevant to tissue pathology in autoimmune diseases are identified based on antigen-binding specificity of the variable region. Only very few autoantibodies, however, mediate pathology by direct interaction with the antigen. In most other cases, the constant region (Fc part) determines antibody-mediated effector functions, such as complement activation, antibodydependent cell-mediated cytotoxicity (ADCC), and engagement of activating or inhibitory Fc receptors (FcR). These Fc-mediated effects are influenced by the amino acid sequence of the Fc part (i.e., antibody isotype and subclass) and by Fc-linked carbohydrate structures. The latter are located in the C␥2 domain of the heavy chain in close proximity to amino acids that interact with FcR and the complement system. Accordingly, Fc-linked carbohydrate structures have recently received increasing attention, since modification of Fc-linked glycan residues of therapeutic antibodies has been shown to strongly influence the therapeutic potential of the antibodies (1-6).

Objective. Anti-citrullinated protein antibodies (ACPAs) display high association with rheumatoid arthritis (RA) and are implicated in its pathogenesis. The presence of ACPAs is known to precede the onset of RA. In order to identify the features that could confer its pathogenicity, we extensively characterized this antibody response in a unique North American native population of patients with RA and their unaffected relatives.Methods. The levels of IgA, IgM, and IgG ACPAs, as well as IgM and IgA rheumatoid factor (RF), were measured in serum samples obtained from 81 patients with RA and 195 of their unaffected relatives. The isotype distribution, the fine specificity of the ACPA response, and its association with RF were compared in health and disease.Results. ACPA positivity was observed in 19% of the healthy relatives and ϳ91% of the patients with RA. ACPA isotype usage was strikingly lower in unaffected relatives than in patients with RA (1-2 versus 5-6 isotypes). Fine specificity studies showed that reactivity to citrullinated fibrinogen and vimentin was present in sera from patients with RA, while it was virtually absent in their unaffected relatives. Finally, the ACPA and RF responses were associated in patients with RA but were discordant in their healthy relatives. Extended analyses revealed that the presence of ACPAs was associated with RA irrespective of RF status, while the association of RF with disease relied on its interaction with ACPAs.Conclusion. The fine specificity and isotype usage of the ACPA response are qualitatively different in health and disease. Epitope spreading and expansion of the isotype repertoire might be necessary for development of RA, and this could be facilitated by the presence of RF antibodies.Autoantibodies are characteristic of a large number of autoimmune diseases. Determining the pathogenicity of autoantibodies by showing their capacity to transfer disease, however, is complicated by ethical and practical difficulties. Therefore, only a small minority of autoantibodies, such as antiplatelet antibodies in idiopathic thrombocytopenia purpura or the antidesmoglein antibodies in pemphigus vulgaris, were convincingly shown to mediate a pathogenetic effect through placental transfer (1) or transfer into experimental animals (2), respectively.

Objective. Remission has become an attainable goal of rheumatoid arthritis (RA) treatment, especially since the advent of biologic antirheumatic therapy. Because little is known about patients who achieve disease remission with conventional treatment, we used 2 large independent inception cohorts to study the prevalence of and predictive factors for diseasemodifying antirheumatic drug (DMARD)-free sustained remission after treatment with conventional therapy.Methods. Remission of disease was assessed in 454 patients from the Leiden Early Arthritis Clinic (EAC) and in 895 patients from the British Early Rheumatoid Arthritis Study (ERAS) who fulfilled the American College of Rheumatology 1987 revised criteria for the classification of RA and were treated with conventional therapy. Sustained DMARD-free remission was defined as fulfilling the following criteria for at least 1 year: 1) no current DMARD use, 2) no swollen joints, and 3) classification as DMARD-free remission by the patient's rheumatologist. Predictive factors were identified by Cox regression analysis.Results. Sustained DMARD-free remission was achieved by 68 of 454 patients (15.0%) in the Leiden EAC and by 84 of 895 patients (9.4%) in the ERAS. Six factors were associated with sustained DMARD-free remission in both cohorts: acute onset, short symptom duration before inclusion, not smoking, little radiographic damage at baseline, absence of IgM rheumatoid factor (IgM-RF), and absence of HLA shared epitope alleles. In the ERAS, low disease activity at baseline was also predictive of remission. Multivariate analyses revealed symptom duration and the absence of autoantibodies (anti-cyclic citrullinated peptide 2 and IgM-RF) as independent predictors.Conclusion. Sustained DMARD-free remission in RA patients treated with conventional therapy is not uncommon. Symptom duration at presentation and the absence of autoantibodies are associated with sustained DMARD-free remission.

Objective. It has been suggested that anticitrullinated protein antibodies (ACPAs) play an important role in the pathogenesis of rheumatoid arthritis (RA). To exert their pathologic effects, ACPAs must recruit immune effector mechanisms such as activation of the complement system. Mouse models of RA have shown that, surprisingly, arthritogenic antibodies activate the alternative pathway of complement rather than the expected classical pathway. This study was undertaken to investigate whether human anti-cyclic citrullinated peptide (anti-CCP) antibodies activate the complement system in vitro and, if so, which pathways of complement activation are used.Methods. We set up novel assays to analyze complement activation by anti-CCP antibodies, using cyclic citrullinated peptide-coated plates, specific buffers, and normal and complement-deficient sera as a source of complement.Results. Anti-CCP antibodies activated complement in a dose-dependent manner via the classical pathway of complement, and, surprisingly, via the alternative pathway of complement. The lectin pathway was not activated by anti-CCP antibodies. Complement activation proceeded in vitro up to the formation of the membrane attack complex, indicating that all activation steps, including the release of C5a, took place.Conclusion. Our findings indicate that anti-CCP antibodies activate the complement system in vitro via the classical and alternative pathways but not via the lectin pathway. These findings are relevant for the design of interventions aimed at inhibition of complement-mediated damage in RA.