Identification of anticitrullinated protein antibody reactivities in a subset of anti-CCP-negative rheumatoid arthritis: association with cigarette smoking and HLA-DRB1 ‘shared epitope’ alleles

Abstract

IntroductionA hallmark of rheumatoid arthritis (RA) is the development of autoantibodies targeting proteins that contain citrulline. Anticitrullinated protein antibodies (ACPAs) are currently detected by the commercial cyclic citrullinated peptide (CCP) assay, which uses a mix of cyclised citrullinated peptides as an artificial mimic of the true antigen(s). To increase the sensitivity of ACPA detection and dissect ACPA specificities, we developed a multiplex assay that profiles ACPAs by measuring their reactivity to the citrullinated peptides and proteins derived from RA joint tissue.MethodsWe created a bead-based, citrullinated antigen array to profile ACPAs. This custom array contains 16 citrullinated peptides and proteins detected in RA synovial tissues. We used the array to profile ACPAs in sera from a cohort of patients with RA and other non-inflammatory arthritides, as well as sera from an independent cohort of RA patients for whom data were available on carriage of HLA-DRB1 ‘shared epitope’ (SE) alleles and history of cigarette smoking.ResultsOur multiplex assay showed that at least 10% of RA patients who tested negative in the commercial CCP assay possessed ACPAs. Carriage of HLA-DRB1 SE alleles and a history of cigarette smoking were associated with an increase in ACPA reactivity—in anti-CCP+ RA and in a subset of anti-CCP− RA.ConclusionsOur multiplex assay can identify ACPA-positive RA patients missed by the commercial CCP assay, thus enabling greater diagnostic sensitivity. Further, our findings suggest that cigarette smoking and possession of HLA-DRB1 SE alleles contribute to the development of ACPAs in anti-CCP− RA.

Antibodies to native and citrullinated RA33 (hnRNP A2/B1) challenge citrullination as the inciting principle underlying loss of tolerance in rheumatoid arthritis

“…Applying the antigen-centric model, the transition of an anti-native protein to an anti-citrullinated protein antibody response may depend on the presence of permissive factors, that is, a genetic predisposition allowing for presentation (HLA alleles) and the continued production of modified antigen (chronic bacterial infection, smoking or immune-mediated membranolysis resulting in secondary release of modified autoantigens into the extracellular compartment of the RA joint) 4 36 38 39 40. In the individual at risk, concurrence of these factors, timing and stochastic events may define whether antibody transition occurs during the pre-RA phase, once the disease is established, or not at all (ACPA-negative RA).…”

Anti-phospholipid Antibodies and Smoking: An Overview

“…Smoking has also been strongly linked to the development of anti-citrullinated protein antibodies (ACPAs) commonly seen in RA patients [101], including RA patients who are negative for anti-CCP [102]. Recent research has suggested that periodontitis and P. gingivalis infection are associated with citrullination through the action of peptidylarginine deiminase [87,103].…”

Development of a Multiantigen Panel for Improved Detection of Borrelia burgdorferi Infection in Early Lyme Disease

“…Synthetic peptides which represent lipoprotein epitopes are in the unprocessed form. Each antigen marker was conjugated to spectrally distinct beads using Luminex technology and established methods (23). The pooled antigen panel was incubated with serum samples, and binding was separately assayed using anti-human IgG conjugated to phycoerythrin (PE) or anti-human IgM-PE.…”

“…Multiplex approaches have the potential to improve sensitivity and specificity of the current technology by assessing antibody responses to multiple B. burgdorferi proteins and these novel peptide markers simultaneously (21)(22)(23)(24)(25). Such platforms may detect cases where a patient is not responsive to the main immunodominant epitope, where the infecting subspecies of B. burgdorferi is polymorphic at the immunodominant epitope, or where temporal variations in antigen or antibody limit tests based on singleantibody detection (26).…”