Is periodontal disease a risk factor for rheumatoid arthritis? The anticitrullinated antibody repertoire in periodontal disease

Background Anticitrullinated peptide antibodies (ACPA) epitope spreading has been shown to occur several years prior to RA clinical onset. Recent studies suggest an association between rheumatoid arthritis (RA) and periodontal disease (PD). Since P gingivalis is a common periodontal pathogen with a peptidylarginine deiminase that citrullinates proteins, the authors hypothesised that PD may have a causal role in the aetiology of RA. The purpose was to determine the immune reactivities to citrullinated antigens in subjects with and without PD. Methods Participants were recruited from the Birmingham Dental Hospital, Birmingham, UK. The presence of PD was based on a periodontal examination and/or radiographs. ACPA presence was determined on serum samples. In addition to anti-CCP2 and anti-MCV, the authors tested for antibodies with specificity for different citrullinated peptides, including α-enolase peptide 1 (CEP-1), fibrinogen (cit-fib) and vimentin (cit-vim). Antibodies against the uncitrullinated form of the same peptides were determined as negative controls. Comparisons between groups were done using χ2 or Mann–Whitney as appropriate. Non-normally distributed variables were log transformed for analyses using linear regression models. Results The total sample included 194 subjects of whom 81 had PD and 113 did not (non-PD). None of the participants had RA at the time of the study. As expected, there was a low frequency of ACPA, including anti-CCP2, anti-MCV, anti-CEP-1, anti-cit-vim and anti-cit-fib. Anti-CCP2 antibodies were present in 1.3% of the PD group and none of the controls. Anti-MCV was present in one subject in each of the groups. Anti-CEP-1 antibodies and anti-REP1 (arginine control peptide for CEP-1) were present in 8.6% and 1.8% (p=0.02) and 38.3% and 14.2% (p<0.001) of the cases and controls, respectively. Among those with PD, those who were anti-CEP-1 positive were non-smokers and among those who were anti-REP-1 positive only 13% were smokers. Anti-fib antibodies (arginine control peptide for ...