Background There is little evidence on prediction of clinical response to biologics in patients with RA. Recently, it has been suggested that clinical response to tumor necrosis factor (TNF) inhibitors was related to periodontal conditions, which might be affected by infection with Porphyromonas gingivalis. Additionally, serum antibody responses to P. gingivalis were associated with RA and periodontitis.
Objectives To evaluate whether serum antibody responses to P. gingivalis antigens and periodontal conditions are associated with clinical response to biologics in patients with RA.
Methods Sixteen patients with severe RA enrolled in this study were treated with biologics according to the usual regimen (7 patients with TNF inhibitors, 6 with IL-6 blocker and 3 with CTLA-4 Ig). DAS28-CRP was evaluated at 3 months (reassessment) after the initiation of biologics. Periodontal conditions were assessed by two calibrated periodontists for the following measurements; number of teeth present, probing depth (PD), clinical attachment level (CAL), plaque control record (PCR), and bleeding on plobing (BOP). Serum levels of antibodies against P. gingivalis sonicated extracts (SE) and outer membrane protein (OMP) and anti-CCP antibodies were determined by enzyme-linked immunsorbent assay, respectively, prior to the start of medication with biologics (baseline).
Results Their mean (SD) age was 55.9 (15) years. Patients were predominantly women (81%) with mean disease duration of 8.2(6) years. Most patients had active disease with DAS28-CRP 4.2 (0.9) at baseline, and showed an improvement of DAS28-CRP 2.77 (0.85) at reassessment. Six patients (38%) achieved remission (DAS28-CRP<2.3) at reassessment. The mean serum levels of anti-CCP antibodies were 474.6 (1001.8), and the mean serum levels of antibodies against P. gingivalis SE and OMP 2.37 (3.41)and 0.605 (0.274), respectively at baseline. Periodontal conditions of the patients were as follows; mean PD was 2.84 (0.37) (mm), mean CAL was 3.2 (0.85) (mm), mean PCR was 0.61 (0.41) (%), and mean BOP was 0.33 (0.16) (%) at baseline. No associations were observed between changes in DAS28-CRP (delta-DAS28-CRP) and serum and periodontal parameter values (serum levels of antibodies against P. gingivalis SE and OMP, PD, CAL, PCR, and BOP). However, a significant correlation was found between delta-DAS28-CRP and serum levels of anti-CCP antibodies (P = 0.02, r = 0.56).
Conclusions These results failed to show an association of the serum antibody responses to P. gingivalis antigens and periodontal conditions with clinical response to biologics in patients with RA. However, it is suggested that serum anti-CCP antibody titer constitute a factor predicting clinical response to biologics. Further studies would be required to fully evaluate the association with a larger population.
C, Savioli et al. Ann Rheum Dis 70(Suppl3):566(2011)
Kobayashi, T. et al. J Periodontol.77,364-69(2006)
Disclosure of Interest None Declared