AB0119 Rheumatoid arthritis (RA)-associated autoantibodies are present in the periodontal exudate of patients with and without ra

Abstract

Background Seropositivity for anti-citrullinated protein antibodies (ACPA) and rheumatoid factor (RF) is a hallmark of RA and can be present years before clinical disease onset. Environmental factors, including smoking and chronic inflamed mucosal tissues of the lungs, gastro-intestinal tract or oral cavity (i.e., the periodontium) are suggested to contribute to initiation of these autoantibodies. While it is known that the inflamed periodontium contains citrullinated proteins and peptides, only Harvey et al. (2013) showed that IgG ACPA is indeed present in periodontal exudate (n=9). Objectives As the IgA isotype is specific for mucosal immunity, we assessed in patients with and without RA whether IgA RF and IgA ACPA are present gingivocrevicular fluid (GCF), i.e., the periodontal inflammatory exudate. Methods RA patients fulfilling the ACR/EULAR 2010 classification criteria were recruited at the Rheumatology department of the Dr. Sardjito General Hospital, Yogyakarta, Indonesia. Patients without RA (non-RA) were recruited from the Oral and Maxillofacial Surgery department of the same hospital. In both groups, patients with diabetes or cardiovascular disease were excluded. Periodontitis was defined as periodontal inflamed surface area (PISA) >130 mm2 (Leira et al. 2017). RF and ACPA were determined by ELISA in serum (IgM RF, IgA RF, IgG ACPA, IgA ACPA) and GCF (IgA RF, IgA ACPA). Total IgG and IgA were determined in GCF. IgA ACPA seropositivity and IgA RF- and IgA ACPA positivity in GCF were defined as >mean +2 SD of healthy controls (non-RA patients, never smokers, no periodontitis, n=88). ![Abstract AB0119 – Figure 1][1] Abstract AB0119 – Figure 1 Non-RA patients (n=151) Results In non-RA patients (n=151), PISA was correlated with total IgG and IgA in GCF (p<0.0001). IgA RF and IgA ACPA were present in GCF and correlated with total IgA in GCF (p<0.05 and p<0.01 respectively). In contrast to RA patients (n=72), IgA RF and IgA ACPA in GCF of non-RA patients did not correlate with IgA RF and IgA ACPA in serum. In non-RA patients, IgA ACPA positivity in GCF was more frequent in ever smokers (18%) than in never smokers (9.8%); the same held for presence or absence of periodontitis (18% and 9.3% IgA ACPA positivity, respectively). In non-RA patients PISA was correlated with IgA ACPA in serum (p<0.01) and GCF (p=0.05) (figure 1). Conclusions RA-associated autoantibodies are present in GCF of patients with and without RA. In contrast to RA patients, in whom this presence is probably due to leakage from serum, presence of RA-associated autoantibodies in GCF of patients without RA is presumably the result of local formation of these autoantibodies due to periodontitis. References [1] Harvey, et al. J Periodontal Res2013;48:252–61. [2] Leira, et al. Acta Odontol Scand2017Nov 11:1–4. Disclosure of Interest None declared [1]: pending:yes