Periodontal pathogens participate in synovitis in patients with rheumatoid arthritis in clinical remission: a retrospective case-control study

Objective. The objective of this study was to investigate the role of periodontal pathogens in RA in remission. Methods. Twenty-one patients with active RA and 70 patients in clinical remission, including 48 patients with synovitis [US power Doppler (USPD)(+) group] and 22 patients without synovitis [USPD(-) group] were clinically assessed by US. CRP, ESR, haemoglobin, MMP-3, RF and ACPA were measured. Antibody titres against four types of periodontal pathogen [Aggregatibacter actinomycetemcomitans, Eikenella corrodens (Ec), Porphyromonas gingivalis and Prevotella intermedia (Pi)] were analysed using ELISA. Results. Musculoskeletal US examination showed that 68.6% of patients with RA in clinical remission exhibited synovitis. CRP, ESR, haemoglobin, MMP-3 and RF levels in both the USPD(+) and USPD(-) groups were clearly lower compared with the RA group in non-remission. The IgG serum antibody titre against Ec in the non-remission RA(+) group was significantly greater than that in the USPD(+) group, and the IgG antibody titre against Pi in the non-remission RA and USPD(+) groups was greater than in the USPD(-) group. Conclusion. More than half of RA patients in remission showed persistent synovitis. This synovitis may be associated with periodontal disease-causing Pi. Thus, treating periodontal disease should also be considered in order to achieve more profound remission of RA.